refactor(core): make boot_ucb/header implementation hw specific

diff --git a/core/SConscript.kernel b/core/SConscript.kernel
index cb0e64d0..7b931e37 100644
--- a/core/SConscript.kernel
+++ b/core/SConscript.kernel
@@ -225,7 +225,7 @@ SOURCE_MOD += [
     'embed/rtl/error_handling.c',
     'embed/rtl/scm_revision.c',
     'embed/rtl/strutils.c',
-    'embed/sec/image/boot_image.c',
+    'embed/sec/image/stm32/boot_image.c',
     'embed/sec/image/image.c',
     'embed/sec/rsod/rsod_special.c',
     'vendor/micropython/lib/uzlib/adler32.c',
diff --git a/core/SConscript.prodtest b/core/SConscript.prodtest
index e42179e9..b19db13f 100644
--- a/core/SConscript.prodtest
+++ b/core/SConscript.prodtest
@@ -167,7 +167,7 @@ SOURCE_MOD += [
     'embed/rtl/scm_revision.c',
     'embed/rtl/strutils.c',
     'embed/rtl/unit_test.c',
-    'embed/sec/image/boot_image.c',
+    'embed/sec/image/stm32/boot_image.c',
     'embed/sec/image/image.c',
     'embed/sec/rsod/rsod_special.c',
     'vendor/micropython/lib/uzlib/adler32.c',
diff --git a/core/SConscript.prodtest_emu b/core/SConscript.prodtest_emu
index d67ab125..c2f13029 100644
--- a/core/SConscript.prodtest_emu
+++ b/core/SConscript.prodtest_emu
@@ -136,7 +136,7 @@ SOURCE_MOD += [
     'embed/rtl/scm_revision.c',
     'embed/rtl/strutils.c',
     'embed/rtl/unit_test.c',
-    'embed/sec/image/boot_image.c',
+    'embed/sec/image/stm32/boot_image.c',
     'embed/sec/image/image.c',
     'embed/sec/rsod/rsod_special.c',
     'vendor/micropython/lib/uzlib/adler32.c',
diff --git a/core/SConscript.secmon b/core/SConscript.secmon
index 990b0a93..f7c5e8a2 100644
--- a/core/SConscript.secmon
+++ b/core/SConscript.secmon
@@ -220,7 +220,7 @@ SOURCE_MOD += [
     'embed/io/translations/translations.c',
     'embed/rtl/error_handling.c',
     'embed/rtl/strutils.c',
-    'embed/sec/image/boot_image.c',
+    'embed/sec/image/stm32/boot_image.c',
     'embed/sec/image/image.c',
     'embed/sec/rsod/rsod_special.c',
     'vendor/micropython/lib/uzlib/adler32.c',
diff --git a/core/embed/sec/image/boot_header.c b/core/embed/sec/image/boot_header.c
deleted file mode 100644
index ec2ca636..00000000
--- a/core/embed/sec/image/boot_header.c
+++ /dev/null
@@ -1,275 +0,0 @@
-/*
- * This file is part of the Trezor project, https://trezor.io/
- *
- * Copyright (c) SatoshiLabs
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifdef SECURE_MODE
-
-#include <trezor_model.h>
-#include <trezor_rtl.h>
-
-#include <rtl/sizedefs.h>
-#include <sec/boot_header.h>
-#include <sec/image_hash_conf.h>
-
-#include <../vendor/sphincsplus/ref/api.h>
-#include <ed25519-donna/ed25519.h>
-
-static const uint8_t * const BOARDLOADER_PQ_KEYS[] = {
-#if BOOTLOADER_DEVEL
-    (const uint8_t*) "\xec\x01\xe6\x02\x63\x02\x4f\x7e\x71\x72\x80\x13\xb7\x31\xf7\xba\x12\x99\xf5\x18\xc2\x7b\xa3\xed\x8f\x4a\x21\x99\x74\x12\x7c\x62",
-    (const uint8_t*) "\x8a\xf8\x87\x80\x85\x94\x6e\xd8\xb1\x16\xbd\x24\xc0\xf2\xaa\xc4\x8b\x7e\x8f\x11\xbf\x06\x87\x25\xcc\xfb\xb1\x52\xab\xf7\xa4\xcd",
-#else
-    MODEL_BOARDLOADER_PQ_KEYS
-#endif
-};
-
-static const uint8_t * const BOARDLOADER_EC_KEYS[] = {
-#if BOOTLOADER_DEVEL
-    (const uint8_t*) "\xdb\x99\x5f\xe2\x51\x69\xd1\x41\xca\xb9\xbb\xba\x92\xba\xa0\x1f\x9f\x2e\x1e\xce\x7d\xf4\xcb\x2a\xc0\x51\x90\xf3\x7f\xcc\x1f\x9d",
-    (const uint8_t*) "\x21\x52\xf8\xd1\x9b\x79\x1d\x24\x45\x32\x42\xe1\x5f\x2e\xab\x6c\xb7\xcf\xfa\x7b\x6a\x5e\xd3\x00\x97\x96\x0e\x06\x98\x81\xdb\x12",
-#else
-    MODEL_BOARDLOADER_EC_KEYS
-#endif
-};
-
-secbool boot_header_check_signature(const boot_header_auth_t* hdr,
-                                    const merkle_proof_node_t* merkle_root) {
-  // Get the signature indices based on the signature mask
-  _Static_assert(ARRAY_LENGTH(BOARDLOADER_PQ_KEYS) <= 3);
-  _Static_assert(ARRAY_LENGTH(BOARDLOADER_EC_KEYS) ==
-                 ARRAY_LENGTH(BOARDLOADER_PQ_KEYS));
-
-  uint8_t sigmask = hdr->sigmask;
-  uint8_t sigmask_inv = 0;  // FIH
-
-  const boot_header_unauth_t* sig = boot_header_unauth_get(hdr);
-
-  for (int sig_idx = 0; sig_idx < ARRAY_LENGTH(sig->ec_signature); sig_idx++) {
-    // Get the index of the public key in the signature mask
-    int key_idx = __builtin_ctz(sigmask);
-    if (key_idx >= ARRAY_LENGTH(BOARDLOADER_PQ_KEYS)) {
-      return secfalse;
-    }
-
-    // Hash of the Merkle root and the SLH signature
-    uint8_t hash[IMAGE_HASH_DIGEST_LENGTH];
-    IMAGE_HASH_CTX ctx;
-    IMAGE_HASH_INIT(&ctx);
-    IMAGE_HASH_UPDATE(&ctx, merkle_root->bytes, sizeof(merkle_root->bytes));
-    IMAGE_HASH_UPDATE(&ctx, sig->slh_signature[sig_idx],
-                      sizeof(sig->slh_signature[sig_idx]));
-    IMAGE_HASH_FINAL(&ctx, hash);
-
-    // Verify EC signature - do it before we verify the PQC signature
-    int ec_result =
-        ed25519_sign_open(hash, sizeof(hash), BOARDLOADER_EC_KEYS[key_idx],
-                          sig->ec_signature[sig_idx]);
-
-    if (ec_result != 0) {
-      return secfalse;
-    }
-
-    // Verify the PQC signature
-    int pq_result = crypto_sign_verify(
-        sig->slh_signature[sig_idx], sizeof(sig->slh_signature[sig_idx]),
-        merkle_root->bytes, sizeof(merkle_root->bytes),
-        BOARDLOADER_PQ_KEYS[key_idx]);
-
-    if (pq_result != 0) {
-      return secfalse;
-    }
-
-    // Mark the key as used
-    sigmask &= ~(1 << key_idx);
-    sigmask_inv |= (1 << key_idx);
-  }
-
-  if (sigmask != 0 || sigmask_inv != hdr->sigmask) {  // FIH
-    // There were more than BOOT_HEADER_SIGNATURE_COUNT public key bits
-    // set or some of the public keys in the original sigmask were not used.
-    return secfalse;
-  }
-
-  return sectrue;
-}
-
-static size_t boot_header_merkle_proof_size(
-    const boot_header_merkle_proof_t* proof) {
-  return sizeof(boot_header_merkle_proof_t) +
-         proof->node_count * sizeof(proof->nodes[0]);
-}
-
-static const boot_header_merkle_proof_t* boot_header_get_merkle_proof(
-    const boot_header_auth_t* hdr) {
-  // Check if the merkle_proof.path_len field is within the header
-  if (hdr->auth_size + sizeof(boot_header_merkle_proof_t) > hdr->header_size) {
-    return NULL;
-  }
-
-  // Merkle proof is located right after the authenticated part of the header
-  boot_header_merkle_proof_t* proof =
-      (boot_header_merkle_proof_t*)((uintptr_t)hdr + hdr->auth_size);
-
-  // Check if the path length is in reasonable limits
-  if (proof->node_count > BOOT_HEADER_MERKLE_PROOF_MAXLEN) {
-    return NULL;
-  }
-
-  size_t proof_size = boot_header_merkle_proof_size(proof);
-
-  // Check if the Merkle proof is completely within the header
-  if (hdr->auth_size + proof_size > hdr->header_size) {
-    return NULL;
-  }
-
-  return proof;
-}
-
-const boot_header_auth_t* boot_header_auth_get(uint32_t address) {
-  boot_header_auth_t* hdr = (boot_header_auth_t*)address;
-
-  // Check if the header starts with the magic
-  if (hdr->magic != BOOT_HEADER_MAGIC_TRZQ) {
-    return NULL;
-  }
-
-  // Check if the header size (= bootloader code offset) is aligned to 8K
-  // boundary (flash page size)
-  if (!IS_ALIGNED(hdr->header_size, SIZE_8K) || hdr->header_size == 0) {
-    return NULL;
-  }
-
-  // Check if the header size is in reasonable limits
-  if (hdr->header_size >= SIZE_64K) {
-    return NULL;
-  }
-
-  // Check if the authenticated part size is within the header size
-  if (hdr->auth_size >= hdr->header_size) {
-    return NULL;
-  }
-
-  // Check if the size of the authenticated part is at least the size of the
-  // authenticated boot header structure. This condition prevents updating
-  // to an image whose authenticated part is smaller than the current
-  // authenticated boot header structure.
-  if (hdr->auth_size < sizeof(boot_header_auth_t)) {
-    return NULL;
-  }
-
-  // Check if bootloader code size is within reasonable limits
-  if (hdr->code_size < SIZE_8K) {
-    return NULL;
-  }
-
-  // Check if the hardware model and revision match
-  if (hdr->hw_model != HW_MODEL || hdr->hw_revision != HW_REVISION) {
-    return secfalse;
-  }
-
-  // Check if the header contains a valid Merkle proof
-  if (NULL == boot_header_get_merkle_proof(hdr)) {
-    return NULL;
-  }
-
-  // Check if the header contains a valid unauthenticated part
-  if (NULL == boot_header_unauth_get(hdr)) {
-    return NULL;
-  }
-
-  return hdr;
-}
-
-const boot_header_unauth_t* boot_header_unauth_get(
-    const boot_header_auth_t* hdr) {
-  const boot_header_merkle_proof_t* proof = boot_header_get_merkle_proof(hdr);
-
-  if (proof == NULL) {
-    // If the Merkle proof is invalid, the unauthenticated part cannot
-    // be valid either
-    return NULL;
-  }
-
-  size_t proof_size = boot_header_merkle_proof_size(proof);
-
-  // Unauthenticated part is located right after the Merkle proof
-  boot_header_unauth_t* unauth =
-      (boot_header_unauth_t*)((uintptr_t)proof + proof_size);
-
-  // Check if the unauthenticated part is within the header
-  if (hdr->auth_size + proof_size + sizeof(boot_header_unauth_t) >
-      hdr->header_size) {
-    return NULL;
-  }
-
-  return unauth;
-}
-
-void boot_header_calc_merkle_root(const boot_header_auth_t* hdr,
-                                  uint32_t code_address,
-                                  merkle_proof_node_t* root) {
-  IMAGE_HASH_CTX ctx;
-
-  static const uint8_t prefix0[] = {0x00};
-  static const uint8_t prefix1[] = {0x01};
-
-  // Hash the bootloader code
-  IMAGE_HASH_INIT(&ctx);
-  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)code_address, hdr->code_size);
-  IMAGE_HASH_FINAL(&ctx, root->bytes);
-
-  // Hash the authenticated part of the header
-  IMAGE_HASH_INIT(&ctx);
-  IMAGE_HASH_UPDATE(&ctx, prefix0, sizeof(prefix0));
-  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)hdr, hdr->auth_size);
-  IMAGE_HASH_UPDATE(&ctx, root->bytes, sizeof(root->bytes));
-  IMAGE_HASH_FINAL(&ctx, root->bytes);
-
-  const boot_header_merkle_proof_t* proof = boot_header_get_merkle_proof(hdr);
-
-  // Add the Merkle proof nodes to the hash
-  for (size_t i = 0; i < proof->node_count; i++) {
-    const merkle_proof_node_t* node = &proof->nodes[i];
-    IMAGE_HASH_INIT(&ctx);
-    IMAGE_HASH_UPDATE(&ctx, prefix1, sizeof(prefix1));
-    if (memcmp(node, root->bytes, sizeof(root->bytes)) < 0) {
-      IMAGE_HASH_UPDATE(&ctx, node->bytes, sizeof(node->bytes));
-      IMAGE_HASH_UPDATE(&ctx, root->bytes, sizeof(root->bytes));
-    } else {
-      IMAGE_HASH_UPDATE(&ctx, root->bytes, sizeof(root->bytes));
-      IMAGE_HASH_UPDATE(&ctx, node->bytes, sizeof(node->bytes));
-    }
-    IMAGE_HASH_FINAL(&ctx, root->bytes);
-  }
-}
-
-secbool bootloader_area_needs_update(const boot_header_auth_t* hdr,
-                                     uint32_t code_address) {
-  boot_header_auth_t* prev_hdr = (boot_header_auth_t*)BOOTLOADER_START;
-  if (hdr->header_size == prev_hdr->header_size &&
-      hdr->code_size == prev_hdr->code_size &&
-      (memcmp(hdr, prev_hdr, hdr->header_size) == 0) &&
-      (memcmp((const uint8_t*)code_address,
-              (const uint8_t*)prev_hdr + prev_hdr->header_size,
-              hdr->code_size) == 0)) {
-    return secfalse;
-  }
-  return sectrue;
-}
-
-#endif  // SECURE_MODE
diff --git a/core/embed/sec/image/boot_image.c b/core/embed/sec/image/boot_image.c
deleted file mode 100644
index b3e100f1..00000000
--- a/core/embed/sec/image/boot_image.c
+++ /dev/null
@@ -1,290 +0,0 @@
-/*
- * This file is part of the Trezor project, https://trezor.io/
- *
- * Copyright (c) SatoshiLabs
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifdef SECURE_MODE
-
-#include <trezor_model.h>
-#include <trezor_rtl.h>
-
-#include <sec/board_capabilities.h>
-#include <sec/boot_image.h>
-#include <sec/image.h>
-#include <sec/monoctr.h>
-#include <sys/flash.h>
-#include <sys/mpu.h>
-
-#include "blake2s.h"
-#include "memzero.h"
-
-#ifdef USE_BOOT_UCB
-#include <sec/boot_header.h>
-#include <sec/boot_ucb.h>
-#else
-#include "uzlib.h"
-#endif
-
-#ifndef USE_BOOT_UCB
-
-static secbool hash_match(const uint8_t *hash, const uint8_t *hash_00,
-                          const uint8_t *hash_FF) {
-  if (0 == memcmp(hash, hash_00, BLAKE2S_DIGEST_LENGTH)) return sectrue;
-  if (0 == memcmp(hash, hash_FF, BLAKE2S_DIGEST_LENGTH)) return sectrue;
-  return secfalse;
-}
-
-#define UZLIB_WINDOW_SIZE (1 << 10)
-_Static_assert(
-    UZLIB_WINDOW_SIZE >= IMAGE_HEADER_SIZE,
-    "UZLIB_WINDOW_SIZE must be at least as large as IMAGE_HEADER_SIZE");
-_Static_assert(
-    BOOTLOADER_MAXSIZE <= IMAGE_CHUNK_SIZE,
-    "BOOTLOADER_MAXSIZE must be less than or equal to IMAGE_CHUNK_SIZE");
-
-static void uzlib_prepare(struct uzlib_uncomp *decomp, uint8_t *window,
-                          const void *src, uint32_t srcsize, void *dest,
-                          uint32_t destsize) {
-  memzero(decomp, sizeof(struct uzlib_uncomp));
-  if (window) {
-    memzero(window, UZLIB_WINDOW_SIZE);
-  }
-  memzero(dest, destsize);
-  decomp->source = (const uint8_t *)src;
-  decomp->source_limit = decomp->source + srcsize;
-  decomp->dest = (uint8_t *)dest;
-  decomp->dest_limit = decomp->dest + destsize;
-  uzlib_uncompress_init(decomp, window, window ? UZLIB_WINDOW_SIZE : 0);
-}
-
-bool boot_image_check(const boot_image_t *image) {
-  mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
-
-  // compute current bootloader hash
-  uint8_t hash[BLAKE2S_DIGEST_LENGTH];
-  const uint32_t bl_len = flash_area_get_size(&BOOTLOADER_AREA);
-  const void *bl_data = flash_area_get_address(&BOOTLOADER_AREA, 0, bl_len);
-  blake2s(bl_data, bl_len, hash, BLAKE2S_DIGEST_LENGTH);
-
-  // don't whitelist the valid bootloaders for now
-  // ensure(known_bootloader(hash, BLAKE2S_DIGEST_LENGTH), "Unknown bootloader
-  // detected");
-
-  // does the bootloader match?
-  if (sectrue == hash_match(hash, image->hash_00, image->hash_FF)) {
-    mpu_reconfig(mode);
-    return false;
-  }
-
-  mpu_reconfig(mode);
-  return true;
-}
-
-void boot_image_replace(const boot_image_t *image) {
-  const uint32_t bl_len = flash_area_get_size(&BOOTLOADER_AREA);
-  const void *bl_data = flash_area_get_address(&BOOTLOADER_AREA, 0, bl_len);
-
-  mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
-
-  struct uzlib_uncomp decomp = {0};
-  uint8_t decomp_window[UZLIB_WINDOW_SIZE] = {0};
-  uint32_t decomp_out[IMAGE_HEADER_SIZE / sizeof(uint32_t)] = {0};
-
-  uzlib_prepare(&decomp, decomp_window, image->image_ptr, image->image_size,
-                decomp_out, sizeof(decomp_out));
-
-  ensure((uzlib_uncompress(&decomp) == TINF_OK) ? sectrue : secfalse,
-         "Bootloader header decompression failed");
-
-  const image_header *new_bld_hdr = read_image_header(
-      (uint8_t *)&decomp_out, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_MAXSIZE);
-
-  ensure(new_bld_hdr == (const image_header *)&decomp_out ? sectrue : secfalse,
-         "Invalid embedded bootloader");
-
-  ensure(check_image_model(new_bld_hdr), "Incompatible embedded bootloader");
-
-  ensure(check_bootloader_header_sig(new_bld_hdr),
-         "Invalid embedded bootloader signature");
-
-  const image_header *current_bld_hdr =
-      read_image_header(bl_data, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_MAXSIZE);
-
-  uint8_t new_bld_hash[IMAGE_HASH_DIGEST_LENGTH] = {0};
-  uint8_t new_bld_hash_expected[IMAGE_HASH_DIGEST_LENGTH] = {0};
-
-  IMAGE_HASH_CTX ctx;
-  IMAGE_HASH_INIT(&ctx);
-
-  // backup new bld header values, as it will be overwritten by uzlib
-  size_t header_offset = new_bld_hdr->hdrlen;
-  memcpy(new_bld_hash_expected, &new_bld_hdr->hashes[0],
-         IMAGE_HASH_DIGEST_LENGTH);
-  uint32_t new_bld_hw_model = new_bld_hdr->hw_model;
-  uint8_t new_bld_monotonic = new_bld_hdr->monotonic;
-
-  do {
-    uint8_t *p = (uint8_t *)decomp_out + header_offset;
-    uint32_t size = decomp.dest - (uint8_t *)decomp_out - header_offset;
-    IMAGE_HASH_UPDATE(&ctx, p, size);
-    decomp.dest = (uint8_t *)decomp_out;
-    header_offset =
-        0;  // after the first chunk, we don't need to skip the header anymore
-  } while (uzlib_uncompress(&decomp) >= 0);
-
-  IMAGE_HASH_FINAL(&ctx, new_bld_hash);
-
-  if (0 !=
-      memcmp(new_bld_hash, new_bld_hash_expected, IMAGE_HASH_DIGEST_LENGTH)) {
-    // the hash in the header does not match the computed hash
-    error_shutdown("Invalid bootloader contents");
-  }
-
-  memset(&decomp, 0, sizeof(struct uzlib_uncomp));
-
-  // cannot find valid header for current bootloader, something is wrong
-  ensure(current_bld_hdr == (const image_header *)bl_data ? sectrue : secfalse,
-         "Invalid bootloader header");
-
-  ensure(check_image_model(current_bld_hdr), "Incompatible bootloader found");
-
-  if (new_bld_monotonic < current_bld_hdr->monotonic) {
-    error_shutdown("Bootloader downgrade rejected");
-  }
-
-  uint32_t board_name = get_board_name();
-  if (board_name == 0 || strncmp((const char *)&board_name, "T2T1", 4) == 0) {
-    // no board capabilities, assume Model T
-    if ((strncmp((const char *)&new_bld_hw_model, "T2T1", 4) != 0) &&
-        (new_bld_hw_model != 0)) {
-      // reject non-model T bootloader
-      // 0 represents pre-model check bootloader
-      error_shutdown("Incompatible embedded bootloader");
-    }
-  }
-  // at this point, due to the previous check_image_model call, we know that the
-  // new_bld_hdr is
-  //  meant for the same model as this firmware, so we can check the board name
-  //  against the firmware hw_model.
-  else if (board_name != HW_MODEL) {
-    // reject incompatible bootloader
-    error_shutdown("Incompatible embedded bootloader");
-  }
-
-  ensure(flash_area_erase(&BOOTLOADER_AREA, NULL), NULL);
-  ensure(flash_unlock_write(), NULL);
-
-  uint32_t offset = 0;
-
-  uzlib_prepare(&decomp, decomp_window, image->image_ptr, image->image_size,
-                decomp_out, sizeof(decomp_out));
-
-  ensure((uzlib_uncompress(&decomp) == TINF_OK) ? sectrue : secfalse,
-         "Bootloader decompression failed");
-
-  do {
-    uint32_t *p = decomp_out;
-    uint32_t size = decomp.dest - (uint8_t *)decomp_out;
-    uint32_t size_padded = FLASH_ALIGN(size);
-    ensure(flash_area_write_data_padded(&BOOTLOADER_AREA, offset, p, size, 0,
-                                        size_padded),
-           NULL);
-    offset += size_padded;
-    decomp.dest = (uint8_t *)decomp_out;
-  } while (uzlib_uncompress(&decomp) >= 0);
-
-  if (offset < bl_len) {
-    // fill the rest of the bootloader area with 0x00
-    ensure(flash_area_write_data_padded(&BOOTLOADER_AREA, offset, NULL, 0, 0,
-                                        bl_len - offset),
-           NULL);
-  }
-
-  ensure(flash_lock_write(), NULL);
-
-  mpu_reconfig(mode);
-}
-
-#else
-
-bool boot_image_check(const boot_image_t *image) {
-  if (image->image_size < sizeof(boot_header_auth_t)) {
-    // Invalid image size, must be at least the size of the header
-    return false;
-  }
-
-  mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
-
-  boot_header_auth_t *cur_hdr = (boot_header_auth_t *)BOOTLOADER_START;
-  boot_header_auth_t *new_hdr = (boot_header_auth_t *)image->image_ptr;
-
-  bool diff = (cur_hdr->header_size != new_hdr->header_size) ||
-              (memcmp(cur_hdr, new_hdr, cur_hdr->header_size) != 0);
-
-  mpu_restore(mode);
-
-  return diff;
-}
-
-void boot_image_replace(const boot_image_t *image) {
-  uint32_t header_address = (uint32_t)image->image_ptr;
-
-  // Check that image is big enough to hold the header at least
-  ensure(sectrue * (image->image_size >= sizeof(boot_header_auth_t)),
-         "Bootloader image too small");
-
-  // Read bootloader header
-  const boot_header_auth_t *hdr = boot_header_auth_get(header_address);
-  ensure((hdr != NULL) * sectrue, "Invalid bootloader header");
-
-  // Check the image is big enough to hold both header and code
-  ensure(sectrue * (hdr->header_size + hdr->code_size <= image->image_size),
-         "Bootloader image too small");
-
-  // Check monotonic version
-
-  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
-
-  const boot_header_auth_t *old_hdr = boot_header_auth_get(BOOTLOADER_START);
-
-  ensure((old_hdr != NULL) * sectrue, "Invalid current bootloader header");
-
-  uint8_t min_monotonic_version = old_hdr->monotonic_version;
-
-  mpu_restore(mpu_mode);
-
-  ensure(sectrue * (hdr->monotonic_version >= min_monotonic_version),
-         "Bootloader downgrade rejected");
-
-  uint32_t code_address = (uint32_t)image->image_ptr + hdr->header_size;
-
-  // Calculate the Merkle root from the header and the code
-  merkle_proof_node_t merkle_root;
-  boot_header_calc_merkle_root(hdr, code_address, &merkle_root);
-
-  // Check whether the new bootloader is properly signed
-  ensure(boot_header_check_signature(hdr, &merkle_root),
-         "Invalid bootloader signature");
-
-  // Write to update control block
-  ensure(boot_ucb_write(header_address, code_address),
-         "Failed to write boot UCB");
-}
-
-#endif
-
-#endif
diff --git a/core/embed/sec/image/boot_ucb.c b/core/embed/sec/image/boot_ucb.c
deleted file mode 100644
index bed3875b..00000000
--- a/core/embed/sec/image/boot_ucb.c
+++ /dev/null
@@ -1,167 +0,0 @@
-/*
- * This file is part of the Trezor project, https://trezor.io/
- *
- * Copyright (c) SatoshiLabs
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifdef SECURE_MODE
-
-#include <trezor_bsp.h>
-#include <trezor_model.h>
-#include <trezor_rtl.h>
-
-#include <rtl/sizedefs.h>
-#include <sec/boot_header.h>
-#include <sec/boot_ucb.h>
-#include <sec/image_hash_conf.h>
-#include <sys/flash.h>
-#include <sys/mpu.h>
-
-#define BOOT_UCB_MAGIC 0x5A8C7BF3
-
-#if defined(BOOTLOADER) || defined(BOARDLOADER)
-void adjust_to_secure_flash(uint32_t* address) {
-#ifndef TREZOR_EMULATOR
-  if (*address < FLASH_BASE_S) {
-    // Address is in the non-secure flash region, adjust it to point to the
-    // secure flash region.
-    *address += FLASH_BASE_S - FLASH_BASE_NS;
-  }
-#endif
-}
-#endif
-
-secbool boot_ucb_read(boot_ucb_t* ucb) {
-  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTUCB);
-  *ucb = *((const boot_ucb_t*)BOOTUCB_START);
-  mpu_restore(mpu_mode);
-
-  if (ucb->magic != BOOT_UCB_MAGIC) {
-    return secfalse;
-  }
-
-#if defined(BOOTLOADER) || defined(BOARDLOADER)
-  // Addresses in the UCB block may reside in both non-secure and secure
-  // flash regions.  We need to adjust them to point to the secure flash
-  // region in order to proceed.
-  adjust_to_secure_flash(&ucb->header_address);
-  adjust_to_secure_flash(&ucb->code_address);
-#endif
-
-  // Before reading the boot header fields, we need to ensure that it's
-  // located in the valid address range.
-  uint32_t min_address = NONBOARDLOADER_START;
-  uint32_t max_address = NONBOARDLOADER_START + NONBOARDLOADER_MAXSIZE;
-
-  if (ucb->header_address < min_address ||
-      ucb->header_address > max_address - sizeof(boot_header_auth_t)) {
-    return secfalse;
-  }
-
-  const boot_header_auth_t* hdr = (boot_header_auth_t*)ucb->header_address;
-
-  // Get address range where the header and code can be located.
-  // Both header and code must be inside flash area reserved for the
-  // firmware and must not overlap with the address range where
-  // the new bootloader will be written.
-  min_address = NONBOARDLOADER_START + hdr->header_size + hdr->code_size;
-  max_address = NONBOARDLOADER_START + NONBOARDLOADER_MAXSIZE;
-
-  // Check if the entire boot header is within the valid address range
-  if (ucb->header_address < min_address || hdr->header_size > max_address ||
-      ucb->header_address > max_address - hdr->header_size) {
-    return secfalse;
-  }
-
-  // Check if code (if present) is within the valid address range
-  if (ucb->code_address != 0) {
-    if (ucb->code_address < min_address || hdr->code_size > max_address ||
-        ucb->code_address > max_address - hdr->code_size) {
-      return secfalse;
-    }
-  }
-
-  uint8_t hash[IMAGE_HASH_DIGEST_LENGTH];  // Hash of the header
-
-  IMAGE_HASH_CTX ctx;
-  IMAGE_HASH_INIT(&ctx);
-  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)hdr, hdr->header_size);
-  IMAGE_HASH_FINAL(&ctx, hash);
-
-  if (memcmp(hash, ucb->hash, sizeof(hash)) != 0) {
-    // Header hash does not match the one stored in UCB
-    // This can happen if the header was modified after the UCB was written.
-    return secfalse;
-  }
-
-  return sectrue;
-}
-
-secbool boot_ucb_write(uint32_t header_address, uint32_t code_address) {
-  boot_ucb_t ucb = {
-      .magic = BOOT_UCB_MAGIC,
-      .header_address = header_address,
-      .code_address = code_address,
-  };
-
-  // Calculate the hash of the header
-  boot_header_auth_t* hdr = (boot_header_auth_t*)header_address;
-
-  IMAGE_HASH_CTX ctx;
-  IMAGE_HASH_INIT(&ctx);
-  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)hdr, hdr->header_size);
-  IMAGE_HASH_FINAL(&ctx, ucb.hash);
-
-  secbool result = secfalse;
-
-  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTUCB);
-
-  // Erase the UCB area
-  if (sectrue != flash_area_erase(&BOOTUCB_AREA, NULL)) {
-    goto cleanup;
-  }
-
-  if (sectrue != flash_unlock_write()) {
-    goto cleanup;
-  }
-
-  // Write the UCB
-  if (sectrue !=
-      flash_area_write_data(&BOOTUCB_AREA, 0, (const void*)&ucb, sizeof(ucb))) {
-    goto cleanup;
-  }
-
-  ensure(flash_lock_write(), NULL);
-
-  result = sectrue;
-
-cleanup:
-
-  mpu_restore(mpu_mode);
-  return result;
-}
-
-secbool boot_ucb_erase(void) {
-  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTUCB);
-  secbool result = flash_area_is_erased(&BOOTUCB_AREA);
-  if (sectrue != result) {
-    result = flash_area_erase(&BOOTUCB_AREA, NULL);
-  }
-  mpu_restore(mpu_mode);
-  return result;
-}
-
-#endif  // SECURE_MODE
diff --git a/core/embed/sec/image/stm32/boot_header.c b/core/embed/sec/image/stm32/boot_header.c
new file mode 100644
index 00000000..ec2ca636
--- /dev/null
+++ b/core/embed/sec/image/stm32/boot_header.c
@@ -0,0 +1,275 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef SECURE_MODE
+
+#include <trezor_model.h>
+#include <trezor_rtl.h>
+
+#include <rtl/sizedefs.h>
+#include <sec/boot_header.h>
+#include <sec/image_hash_conf.h>
+
+#include <../vendor/sphincsplus/ref/api.h>
+#include <ed25519-donna/ed25519.h>
+
+static const uint8_t * const BOARDLOADER_PQ_KEYS[] = {
+#if BOOTLOADER_DEVEL
+    (const uint8_t*) "\xec\x01\xe6\x02\x63\x02\x4f\x7e\x71\x72\x80\x13\xb7\x31\xf7\xba\x12\x99\xf5\x18\xc2\x7b\xa3\xed\x8f\x4a\x21\x99\x74\x12\x7c\x62",
+    (const uint8_t*) "\x8a\xf8\x87\x80\x85\x94\x6e\xd8\xb1\x16\xbd\x24\xc0\xf2\xaa\xc4\x8b\x7e\x8f\x11\xbf\x06\x87\x25\xcc\xfb\xb1\x52\xab\xf7\xa4\xcd",
+#else
+    MODEL_BOARDLOADER_PQ_KEYS
+#endif
+};
+
+static const uint8_t * const BOARDLOADER_EC_KEYS[] = {
+#if BOOTLOADER_DEVEL
+    (const uint8_t*) "\xdb\x99\x5f\xe2\x51\x69\xd1\x41\xca\xb9\xbb\xba\x92\xba\xa0\x1f\x9f\x2e\x1e\xce\x7d\xf4\xcb\x2a\xc0\x51\x90\xf3\x7f\xcc\x1f\x9d",
+    (const uint8_t*) "\x21\x52\xf8\xd1\x9b\x79\x1d\x24\x45\x32\x42\xe1\x5f\x2e\xab\x6c\xb7\xcf\xfa\x7b\x6a\x5e\xd3\x00\x97\x96\x0e\x06\x98\x81\xdb\x12",
+#else
+    MODEL_BOARDLOADER_EC_KEYS
+#endif
+};
+
+secbool boot_header_check_signature(const boot_header_auth_t* hdr,
+                                    const merkle_proof_node_t* merkle_root) {
+  // Get the signature indices based on the signature mask
+  _Static_assert(ARRAY_LENGTH(BOARDLOADER_PQ_KEYS) <= 3);
+  _Static_assert(ARRAY_LENGTH(BOARDLOADER_EC_KEYS) ==
+                 ARRAY_LENGTH(BOARDLOADER_PQ_KEYS));
+
+  uint8_t sigmask = hdr->sigmask;
+  uint8_t sigmask_inv = 0;  // FIH
+
+  const boot_header_unauth_t* sig = boot_header_unauth_get(hdr);
+
+  for (int sig_idx = 0; sig_idx < ARRAY_LENGTH(sig->ec_signature); sig_idx++) {
+    // Get the index of the public key in the signature mask
+    int key_idx = __builtin_ctz(sigmask);
+    if (key_idx >= ARRAY_LENGTH(BOARDLOADER_PQ_KEYS)) {
+      return secfalse;
+    }
+
+    // Hash of the Merkle root and the SLH signature
+    uint8_t hash[IMAGE_HASH_DIGEST_LENGTH];
+    IMAGE_HASH_CTX ctx;
+    IMAGE_HASH_INIT(&ctx);
+    IMAGE_HASH_UPDATE(&ctx, merkle_root->bytes, sizeof(merkle_root->bytes));
+    IMAGE_HASH_UPDATE(&ctx, sig->slh_signature[sig_idx],
+                      sizeof(sig->slh_signature[sig_idx]));
+    IMAGE_HASH_FINAL(&ctx, hash);
+
+    // Verify EC signature - do it before we verify the PQC signature
+    int ec_result =
+        ed25519_sign_open(hash, sizeof(hash), BOARDLOADER_EC_KEYS[key_idx],
+                          sig->ec_signature[sig_idx]);
+
+    if (ec_result != 0) {
+      return secfalse;
+    }
+
+    // Verify the PQC signature
+    int pq_result = crypto_sign_verify(
+        sig->slh_signature[sig_idx], sizeof(sig->slh_signature[sig_idx]),
+        merkle_root->bytes, sizeof(merkle_root->bytes),
+        BOARDLOADER_PQ_KEYS[key_idx]);
+
+    if (pq_result != 0) {
+      return secfalse;
+    }
+
+    // Mark the key as used
+    sigmask &= ~(1 << key_idx);
+    sigmask_inv |= (1 << key_idx);
+  }
+
+  if (sigmask != 0 || sigmask_inv != hdr->sigmask) {  // FIH
+    // There were more than BOOT_HEADER_SIGNATURE_COUNT public key bits
+    // set or some of the public keys in the original sigmask were not used.
+    return secfalse;
+  }
+
+  return sectrue;
+}
+
+static size_t boot_header_merkle_proof_size(
+    const boot_header_merkle_proof_t* proof) {
+  return sizeof(boot_header_merkle_proof_t) +
+         proof->node_count * sizeof(proof->nodes[0]);
+}
+
+static const boot_header_merkle_proof_t* boot_header_get_merkle_proof(
+    const boot_header_auth_t* hdr) {
+  // Check if the merkle_proof.path_len field is within the header
+  if (hdr->auth_size + sizeof(boot_header_merkle_proof_t) > hdr->header_size) {
+    return NULL;
+  }
+
+  // Merkle proof is located right after the authenticated part of the header
+  boot_header_merkle_proof_t* proof =
+      (boot_header_merkle_proof_t*)((uintptr_t)hdr + hdr->auth_size);
+
+  // Check if the path length is in reasonable limits
+  if (proof->node_count > BOOT_HEADER_MERKLE_PROOF_MAXLEN) {
+    return NULL;
+  }
+
+  size_t proof_size = boot_header_merkle_proof_size(proof);
+
+  // Check if the Merkle proof is completely within the header
+  if (hdr->auth_size + proof_size > hdr->header_size) {
+    return NULL;
+  }
+
+  return proof;
+}
+
+const boot_header_auth_t* boot_header_auth_get(uint32_t address) {
+  boot_header_auth_t* hdr = (boot_header_auth_t*)address;
+
+  // Check if the header starts with the magic
+  if (hdr->magic != BOOT_HEADER_MAGIC_TRZQ) {
+    return NULL;
+  }
+
+  // Check if the header size (= bootloader code offset) is aligned to 8K
+  // boundary (flash page size)
+  if (!IS_ALIGNED(hdr->header_size, SIZE_8K) || hdr->header_size == 0) {
+    return NULL;
+  }
+
+  // Check if the header size is in reasonable limits
+  if (hdr->header_size >= SIZE_64K) {
+    return NULL;
+  }
+
+  // Check if the authenticated part size is within the header size
+  if (hdr->auth_size >= hdr->header_size) {
+    return NULL;
+  }
+
+  // Check if the size of the authenticated part is at least the size of the
+  // authenticated boot header structure. This condition prevents updating
+  // to an image whose authenticated part is smaller than the current
+  // authenticated boot header structure.
+  if (hdr->auth_size < sizeof(boot_header_auth_t)) {
+    return NULL;
+  }
+
+  // Check if bootloader code size is within reasonable limits
+  if (hdr->code_size < SIZE_8K) {
+    return NULL;
+  }
+
+  // Check if the hardware model and revision match
+  if (hdr->hw_model != HW_MODEL || hdr->hw_revision != HW_REVISION) {
+    return secfalse;
+  }
+
+  // Check if the header contains a valid Merkle proof
+  if (NULL == boot_header_get_merkle_proof(hdr)) {
+    return NULL;
+  }
+
+  // Check if the header contains a valid unauthenticated part
+  if (NULL == boot_header_unauth_get(hdr)) {
+    return NULL;
+  }
+
+  return hdr;
+}
+
+const boot_header_unauth_t* boot_header_unauth_get(
+    const boot_header_auth_t* hdr) {
+  const boot_header_merkle_proof_t* proof = boot_header_get_merkle_proof(hdr);
+
+  if (proof == NULL) {
+    // If the Merkle proof is invalid, the unauthenticated part cannot
+    // be valid either
+    return NULL;
+  }
+
+  size_t proof_size = boot_header_merkle_proof_size(proof);
+
+  // Unauthenticated part is located right after the Merkle proof
+  boot_header_unauth_t* unauth =
+      (boot_header_unauth_t*)((uintptr_t)proof + proof_size);
+
+  // Check if the unauthenticated part is within the header
+  if (hdr->auth_size + proof_size + sizeof(boot_header_unauth_t) >
+      hdr->header_size) {
+    return NULL;
+  }
+
+  return unauth;
+}
+
+void boot_header_calc_merkle_root(const boot_header_auth_t* hdr,
+                                  uint32_t code_address,
+                                  merkle_proof_node_t* root) {
+  IMAGE_HASH_CTX ctx;
+
+  static const uint8_t prefix0[] = {0x00};
+  static const uint8_t prefix1[] = {0x01};
+
+  // Hash the bootloader code
+  IMAGE_HASH_INIT(&ctx);
+  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)code_address, hdr->code_size);
+  IMAGE_HASH_FINAL(&ctx, root->bytes);
+
+  // Hash the authenticated part of the header
+  IMAGE_HASH_INIT(&ctx);
+  IMAGE_HASH_UPDATE(&ctx, prefix0, sizeof(prefix0));
+  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)hdr, hdr->auth_size);
+  IMAGE_HASH_UPDATE(&ctx, root->bytes, sizeof(root->bytes));
+  IMAGE_HASH_FINAL(&ctx, root->bytes);
+
+  const boot_header_merkle_proof_t* proof = boot_header_get_merkle_proof(hdr);
+
+  // Add the Merkle proof nodes to the hash
+  for (size_t i = 0; i < proof->node_count; i++) {
+    const merkle_proof_node_t* node = &proof->nodes[i];
+    IMAGE_HASH_INIT(&ctx);
+    IMAGE_HASH_UPDATE(&ctx, prefix1, sizeof(prefix1));
+    if (memcmp(node, root->bytes, sizeof(root->bytes)) < 0) {
+      IMAGE_HASH_UPDATE(&ctx, node->bytes, sizeof(node->bytes));
+      IMAGE_HASH_UPDATE(&ctx, root->bytes, sizeof(root->bytes));
+    } else {
+      IMAGE_HASH_UPDATE(&ctx, root->bytes, sizeof(root->bytes));
+      IMAGE_HASH_UPDATE(&ctx, node->bytes, sizeof(node->bytes));
+    }
+    IMAGE_HASH_FINAL(&ctx, root->bytes);
+  }
+}
+
+secbool bootloader_area_needs_update(const boot_header_auth_t* hdr,
+                                     uint32_t code_address) {
+  boot_header_auth_t* prev_hdr = (boot_header_auth_t*)BOOTLOADER_START;
+  if (hdr->header_size == prev_hdr->header_size &&
+      hdr->code_size == prev_hdr->code_size &&
+      (memcmp(hdr, prev_hdr, hdr->header_size) == 0) &&
+      (memcmp((const uint8_t*)code_address,
+              (const uint8_t*)prev_hdr + prev_hdr->header_size,
+              hdr->code_size) == 0)) {
+    return secfalse;
+  }
+  return sectrue;
+}
+
+#endif  // SECURE_MODE
diff --git a/core/embed/sec/image/stm32/boot_image.c b/core/embed/sec/image/stm32/boot_image.c
new file mode 100644
index 00000000..b3e100f1
--- /dev/null
+++ b/core/embed/sec/image/stm32/boot_image.c
@@ -0,0 +1,290 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef SECURE_MODE
+
+#include <trezor_model.h>
+#include <trezor_rtl.h>
+
+#include <sec/board_capabilities.h>
+#include <sec/boot_image.h>
+#include <sec/image.h>
+#include <sec/monoctr.h>
+#include <sys/flash.h>
+#include <sys/mpu.h>
+
+#include "blake2s.h"
+#include "memzero.h"
+
+#ifdef USE_BOOT_UCB
+#include <sec/boot_header.h>
+#include <sec/boot_ucb.h>
+#else
+#include "uzlib.h"
+#endif
+
+#ifndef USE_BOOT_UCB
+
+static secbool hash_match(const uint8_t *hash, const uint8_t *hash_00,
+                          const uint8_t *hash_FF) {
+  if (0 == memcmp(hash, hash_00, BLAKE2S_DIGEST_LENGTH)) return sectrue;
+  if (0 == memcmp(hash, hash_FF, BLAKE2S_DIGEST_LENGTH)) return sectrue;
+  return secfalse;
+}
+
+#define UZLIB_WINDOW_SIZE (1 << 10)
+_Static_assert(
+    UZLIB_WINDOW_SIZE >= IMAGE_HEADER_SIZE,
+    "UZLIB_WINDOW_SIZE must be at least as large as IMAGE_HEADER_SIZE");
+_Static_assert(
+    BOOTLOADER_MAXSIZE <= IMAGE_CHUNK_SIZE,
+    "BOOTLOADER_MAXSIZE must be less than or equal to IMAGE_CHUNK_SIZE");
+
+static void uzlib_prepare(struct uzlib_uncomp *decomp, uint8_t *window,
+                          const void *src, uint32_t srcsize, void *dest,
+                          uint32_t destsize) {
+  memzero(decomp, sizeof(struct uzlib_uncomp));
+  if (window) {
+    memzero(window, UZLIB_WINDOW_SIZE);
+  }
+  memzero(dest, destsize);
+  decomp->source = (const uint8_t *)src;
+  decomp->source_limit = decomp->source + srcsize;
+  decomp->dest = (uint8_t *)dest;
+  decomp->dest_limit = decomp->dest + destsize;
+  uzlib_uncompress_init(decomp, window, window ? UZLIB_WINDOW_SIZE : 0);
+}
+
+bool boot_image_check(const boot_image_t *image) {
+  mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
+
+  // compute current bootloader hash
+  uint8_t hash[BLAKE2S_DIGEST_LENGTH];
+  const uint32_t bl_len = flash_area_get_size(&BOOTLOADER_AREA);
+  const void *bl_data = flash_area_get_address(&BOOTLOADER_AREA, 0, bl_len);
+  blake2s(bl_data, bl_len, hash, BLAKE2S_DIGEST_LENGTH);
+
+  // don't whitelist the valid bootloaders for now
+  // ensure(known_bootloader(hash, BLAKE2S_DIGEST_LENGTH), "Unknown bootloader
+  // detected");
+
+  // does the bootloader match?
+  if (sectrue == hash_match(hash, image->hash_00, image->hash_FF)) {
+    mpu_reconfig(mode);
+    return false;
+  }
+
+  mpu_reconfig(mode);
+  return true;
+}
+
+void boot_image_replace(const boot_image_t *image) {
+  const uint32_t bl_len = flash_area_get_size(&BOOTLOADER_AREA);
+  const void *bl_data = flash_area_get_address(&BOOTLOADER_AREA, 0, bl_len);
+
+  mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
+
+  struct uzlib_uncomp decomp = {0};
+  uint8_t decomp_window[UZLIB_WINDOW_SIZE] = {0};
+  uint32_t decomp_out[IMAGE_HEADER_SIZE / sizeof(uint32_t)] = {0};
+
+  uzlib_prepare(&decomp, decomp_window, image->image_ptr, image->image_size,
+                decomp_out, sizeof(decomp_out));
+
+  ensure((uzlib_uncompress(&decomp) == TINF_OK) ? sectrue : secfalse,
+         "Bootloader header decompression failed");
+
+  const image_header *new_bld_hdr = read_image_header(
+      (uint8_t *)&decomp_out, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_MAXSIZE);
+
+  ensure(new_bld_hdr == (const image_header *)&decomp_out ? sectrue : secfalse,
+         "Invalid embedded bootloader");
+
+  ensure(check_image_model(new_bld_hdr), "Incompatible embedded bootloader");
+
+  ensure(check_bootloader_header_sig(new_bld_hdr),
+         "Invalid embedded bootloader signature");
+
+  const image_header *current_bld_hdr =
+      read_image_header(bl_data, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_MAXSIZE);
+
+  uint8_t new_bld_hash[IMAGE_HASH_DIGEST_LENGTH] = {0};
+  uint8_t new_bld_hash_expected[IMAGE_HASH_DIGEST_LENGTH] = {0};
+
+  IMAGE_HASH_CTX ctx;
+  IMAGE_HASH_INIT(&ctx);
+
+  // backup new bld header values, as it will be overwritten by uzlib
+  size_t header_offset = new_bld_hdr->hdrlen;
+  memcpy(new_bld_hash_expected, &new_bld_hdr->hashes[0],
+         IMAGE_HASH_DIGEST_LENGTH);
+  uint32_t new_bld_hw_model = new_bld_hdr->hw_model;
+  uint8_t new_bld_monotonic = new_bld_hdr->monotonic;
+
+  do {
+    uint8_t *p = (uint8_t *)decomp_out + header_offset;
+    uint32_t size = decomp.dest - (uint8_t *)decomp_out - header_offset;
+    IMAGE_HASH_UPDATE(&ctx, p, size);
+    decomp.dest = (uint8_t *)decomp_out;
+    header_offset =
+        0;  // after the first chunk, we don't need to skip the header anymore
+  } while (uzlib_uncompress(&decomp) >= 0);
+
+  IMAGE_HASH_FINAL(&ctx, new_bld_hash);
+
+  if (0 !=
+      memcmp(new_bld_hash, new_bld_hash_expected, IMAGE_HASH_DIGEST_LENGTH)) {
+    // the hash in the header does not match the computed hash
+    error_shutdown("Invalid bootloader contents");
+  }
+
+  memset(&decomp, 0, sizeof(struct uzlib_uncomp));
+
+  // cannot find valid header for current bootloader, something is wrong
+  ensure(current_bld_hdr == (const image_header *)bl_data ? sectrue : secfalse,
+         "Invalid bootloader header");
+
+  ensure(check_image_model(current_bld_hdr), "Incompatible bootloader found");
+
+  if (new_bld_monotonic < current_bld_hdr->monotonic) {
+    error_shutdown("Bootloader downgrade rejected");
+  }
+
+  uint32_t board_name = get_board_name();
+  if (board_name == 0 || strncmp((const char *)&board_name, "T2T1", 4) == 0) {
+    // no board capabilities, assume Model T
+    if ((strncmp((const char *)&new_bld_hw_model, "T2T1", 4) != 0) &&
+        (new_bld_hw_model != 0)) {
+      // reject non-model T bootloader
+      // 0 represents pre-model check bootloader
+      error_shutdown("Incompatible embedded bootloader");
+    }
+  }
+  // at this point, due to the previous check_image_model call, we know that the
+  // new_bld_hdr is
+  //  meant for the same model as this firmware, so we can check the board name
+  //  against the firmware hw_model.
+  else if (board_name != HW_MODEL) {
+    // reject incompatible bootloader
+    error_shutdown("Incompatible embedded bootloader");
+  }
+
+  ensure(flash_area_erase(&BOOTLOADER_AREA, NULL), NULL);
+  ensure(flash_unlock_write(), NULL);
+
+  uint32_t offset = 0;
+
+  uzlib_prepare(&decomp, decomp_window, image->image_ptr, image->image_size,
+                decomp_out, sizeof(decomp_out));
+
+  ensure((uzlib_uncompress(&decomp) == TINF_OK) ? sectrue : secfalse,
+         "Bootloader decompression failed");
+
+  do {
+    uint32_t *p = decomp_out;
+    uint32_t size = decomp.dest - (uint8_t *)decomp_out;
+    uint32_t size_padded = FLASH_ALIGN(size);
+    ensure(flash_area_write_data_padded(&BOOTLOADER_AREA, offset, p, size, 0,
+                                        size_padded),
+           NULL);
+    offset += size_padded;
+    decomp.dest = (uint8_t *)decomp_out;
+  } while (uzlib_uncompress(&decomp) >= 0);
+
+  if (offset < bl_len) {
+    // fill the rest of the bootloader area with 0x00
+    ensure(flash_area_write_data_padded(&BOOTLOADER_AREA, offset, NULL, 0, 0,
+                                        bl_len - offset),
+           NULL);
+  }
+
+  ensure(flash_lock_write(), NULL);
+
+  mpu_reconfig(mode);
+}
+
+#else
+
+bool boot_image_check(const boot_image_t *image) {
+  if (image->image_size < sizeof(boot_header_auth_t)) {
+    // Invalid image size, must be at least the size of the header
+    return false;
+  }
+
+  mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
+
+  boot_header_auth_t *cur_hdr = (boot_header_auth_t *)BOOTLOADER_START;
+  boot_header_auth_t *new_hdr = (boot_header_auth_t *)image->image_ptr;
+
+  bool diff = (cur_hdr->header_size != new_hdr->header_size) ||
+              (memcmp(cur_hdr, new_hdr, cur_hdr->header_size) != 0);
+
+  mpu_restore(mode);
+
+  return diff;
+}
+
+void boot_image_replace(const boot_image_t *image) {
+  uint32_t header_address = (uint32_t)image->image_ptr;
+
+  // Check that image is big enough to hold the header at least
+  ensure(sectrue * (image->image_size >= sizeof(boot_header_auth_t)),
+         "Bootloader image too small");
+
+  // Read bootloader header
+  const boot_header_auth_t *hdr = boot_header_auth_get(header_address);
+  ensure((hdr != NULL) * sectrue, "Invalid bootloader header");
+
+  // Check the image is big enough to hold both header and code
+  ensure(sectrue * (hdr->header_size + hdr->code_size <= image->image_size),
+         "Bootloader image too small");
+
+  // Check monotonic version
+
+  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTLOADER);
+
+  const boot_header_auth_t *old_hdr = boot_header_auth_get(BOOTLOADER_START);
+
+  ensure((old_hdr != NULL) * sectrue, "Invalid current bootloader header");
+
+  uint8_t min_monotonic_version = old_hdr->monotonic_version;
+
+  mpu_restore(mpu_mode);
+
+  ensure(sectrue * (hdr->monotonic_version >= min_monotonic_version),
+         "Bootloader downgrade rejected");
+
+  uint32_t code_address = (uint32_t)image->image_ptr + hdr->header_size;
+
+  // Calculate the Merkle root from the header and the code
+  merkle_proof_node_t merkle_root;
+  boot_header_calc_merkle_root(hdr, code_address, &merkle_root);
+
+  // Check whether the new bootloader is properly signed
+  ensure(boot_header_check_signature(hdr, &merkle_root),
+         "Invalid bootloader signature");
+
+  // Write to update control block
+  ensure(boot_ucb_write(header_address, code_address),
+         "Failed to write boot UCB");
+}
+
+#endif
+
+#endif
diff --git a/core/embed/sec/image/stm32/boot_ucb.c b/core/embed/sec/image/stm32/boot_ucb.c
new file mode 100644
index 00000000..bed3875b
--- /dev/null
+++ b/core/embed/sec/image/stm32/boot_ucb.c
@@ -0,0 +1,167 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef SECURE_MODE
+
+#include <trezor_bsp.h>
+#include <trezor_model.h>
+#include <trezor_rtl.h>
+
+#include <rtl/sizedefs.h>
+#include <sec/boot_header.h>
+#include <sec/boot_ucb.h>
+#include <sec/image_hash_conf.h>
+#include <sys/flash.h>
+#include <sys/mpu.h>
+
+#define BOOT_UCB_MAGIC 0x5A8C7BF3
+
+#if defined(BOOTLOADER) || defined(BOARDLOADER)
+void adjust_to_secure_flash(uint32_t* address) {
+#ifndef TREZOR_EMULATOR
+  if (*address < FLASH_BASE_S) {
+    // Address is in the non-secure flash region, adjust it to point to the
+    // secure flash region.
+    *address += FLASH_BASE_S - FLASH_BASE_NS;
+  }
+#endif
+}
+#endif
+
+secbool boot_ucb_read(boot_ucb_t* ucb) {
+  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTUCB);
+  *ucb = *((const boot_ucb_t*)BOOTUCB_START);
+  mpu_restore(mpu_mode);
+
+  if (ucb->magic != BOOT_UCB_MAGIC) {
+    return secfalse;
+  }
+
+#if defined(BOOTLOADER) || defined(BOARDLOADER)
+  // Addresses in the UCB block may reside in both non-secure and secure
+  // flash regions.  We need to adjust them to point to the secure flash
+  // region in order to proceed.
+  adjust_to_secure_flash(&ucb->header_address);
+  adjust_to_secure_flash(&ucb->code_address);
+#endif
+
+  // Before reading the boot header fields, we need to ensure that it's
+  // located in the valid address range.
+  uint32_t min_address = NONBOARDLOADER_START;
+  uint32_t max_address = NONBOARDLOADER_START + NONBOARDLOADER_MAXSIZE;
+
+  if (ucb->header_address < min_address ||
+      ucb->header_address > max_address - sizeof(boot_header_auth_t)) {
+    return secfalse;
+  }
+
+  const boot_header_auth_t* hdr = (boot_header_auth_t*)ucb->header_address;
+
+  // Get address range where the header and code can be located.
+  // Both header and code must be inside flash area reserved for the
+  // firmware and must not overlap with the address range where
+  // the new bootloader will be written.
+  min_address = NONBOARDLOADER_START + hdr->header_size + hdr->code_size;
+  max_address = NONBOARDLOADER_START + NONBOARDLOADER_MAXSIZE;
+
+  // Check if the entire boot header is within the valid address range
+  if (ucb->header_address < min_address || hdr->header_size > max_address ||
+      ucb->header_address > max_address - hdr->header_size) {
+    return secfalse;
+  }
+
+  // Check if code (if present) is within the valid address range
+  if (ucb->code_address != 0) {
+    if (ucb->code_address < min_address || hdr->code_size > max_address ||
+        ucb->code_address > max_address - hdr->code_size) {
+      return secfalse;
+    }
+  }
+
+  uint8_t hash[IMAGE_HASH_DIGEST_LENGTH];  // Hash of the header
+
+  IMAGE_HASH_CTX ctx;
+  IMAGE_HASH_INIT(&ctx);
+  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)hdr, hdr->header_size);
+  IMAGE_HASH_FINAL(&ctx, hash);
+
+  if (memcmp(hash, ucb->hash, sizeof(hash)) != 0) {
+    // Header hash does not match the one stored in UCB
+    // This can happen if the header was modified after the UCB was written.
+    return secfalse;
+  }
+
+  return sectrue;
+}
+
+secbool boot_ucb_write(uint32_t header_address, uint32_t code_address) {
+  boot_ucb_t ucb = {
+      .magic = BOOT_UCB_MAGIC,
+      .header_address = header_address,
+      .code_address = code_address,
+  };
+
+  // Calculate the hash of the header
+  boot_header_auth_t* hdr = (boot_header_auth_t*)header_address;
+
+  IMAGE_HASH_CTX ctx;
+  IMAGE_HASH_INIT(&ctx);
+  IMAGE_HASH_UPDATE(&ctx, (const uint8_t*)hdr, hdr->header_size);
+  IMAGE_HASH_FINAL(&ctx, ucb.hash);
+
+  secbool result = secfalse;
+
+  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTUCB);
+
+  // Erase the UCB area
+  if (sectrue != flash_area_erase(&BOOTUCB_AREA, NULL)) {
+    goto cleanup;
+  }
+
+  if (sectrue != flash_unlock_write()) {
+    goto cleanup;
+  }
+
+  // Write the UCB
+  if (sectrue !=
+      flash_area_write_data(&BOOTUCB_AREA, 0, (const void*)&ucb, sizeof(ucb))) {
+    goto cleanup;
+  }
+
+  ensure(flash_lock_write(), NULL);
+
+  result = sectrue;
+
+cleanup:
+
+  mpu_restore(mpu_mode);
+  return result;
+}
+
+secbool boot_ucb_erase(void) {
+  mpu_mode_t mpu_mode = mpu_reconfig(MPU_MODE_BOOTUCB);
+  secbool result = flash_area_is_erased(&BOOTUCB_AREA);
+  if (sectrue != result) {
+    result = flash_area_erase(&BOOTUCB_AREA, NULL);
+  }
+  mpu_restore(mpu_mode);
+  return result;
+}
+
+#endif  // SECURE_MODE
diff --git a/core/embed/sec/image/unix/boot_ucb.c b/core/embed/sec/image/unix/boot_ucb.c
new file mode 100644
index 00000000..5a6d7c16
--- /dev/null
+++ b/core/embed/sec/image/unix/boot_ucb.c
@@ -0,0 +1,22 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sec/boot_ucb.h>
+
+secbool boot_ucb_erase(void) { return sectrue; }
diff --git a/core/site_scons/models/D002/discovery2.py b/core/site_scons/models/D002/discovery2.py
index fa38a2d0..a5344b85 100644
--- a/core/site_scons/models/D002/discovery2.py
+++ b/core/site_scons/models/D002/discovery2.py
@@ -63,8 +63,8 @@ def configure(
     defines += [("USE_SECRET_KEYS", "1")]
 
     if "boot_ucb" in features_wanted:
-        sources += ["embed/sec/image/boot_header.c"]
-        sources += ["embed/sec/image/boot_ucb.c"]
+        sources += ["embed/sec/image/stm32/boot_header.c"]
+        sources += ["embed/sec/image/stm32/boot_ucb.c"]
         defines += [("USE_BOOT_UCB", "1")]
         features_available.append("boot_ucb")
 
diff --git a/core/site_scons/models/T3W1/trezor_t3w1_revA.py b/core/site_scons/models/T3W1/trezor_t3w1_revA.py
index 18df0e2a..0fcd4aaa 100644
--- a/core/site_scons/models/T3W1/trezor_t3w1_revA.py
+++ b/core/site_scons/models/T3W1/trezor_t3w1_revA.py
@@ -71,8 +71,8 @@ def configure(
     defines += [("USE_SECRET_KEYS", "1")]
 
     if "boot_ucb" in features_wanted:
-        sources += ["embed/sec/image/boot_header.c"]
-        sources += ["embed/sec/image/boot_ucb.c"]
+        sources += ["embed/sec/image/stm32/boot_header.c"]
+        sources += ["embed/sec/image/stm32/boot_ucb.c"]
         defines += [("USE_BOOT_UCB", "1")]
         features_available.append("boot_ucb")
 
diff --git a/core/site_scons/models/T3W1/trezor_t3w1_revB.py b/core/site_scons/models/T3W1/trezor_t3w1_revB.py
index d4837318..a7120292 100644
--- a/core/site_scons/models/T3W1/trezor_t3w1_revB.py
+++ b/core/site_scons/models/T3W1/trezor_t3w1_revB.py
@@ -71,8 +71,8 @@ def configure(
     defines += [("USE_SECRET_KEYS", "1")]
 
     if "boot_ucb" in features_wanted:
-        sources += ["embed/sec/image/boot_header.c"]
-        sources += ["embed/sec/image/boot_ucb.c"]
+        sources += ["embed/sec/image/stm32/boot_header.c"]
+        sources += ["embed/sec/image/stm32/boot_ucb.c"]
         defines += [("USE_BOOT_UCB", "1")]
         features_available.append("boot_ucb")
 
diff --git a/core/site_scons/models/T3W1/trezor_t3w1_revC.py b/core/site_scons/models/T3W1/trezor_t3w1_revC.py
index 7f4c14a8..c42c8048 100644
--- a/core/site_scons/models/T3W1/trezor_t3w1_revC.py
+++ b/core/site_scons/models/T3W1/trezor_t3w1_revC.py
@@ -87,8 +87,8 @@ def configure(
     sources += ["vendor/mldsa-native/mldsa/src/fips202/keccakf1600.c"]
 
     if "boot_ucb" in features_wanted:
-        sources += ["embed/sec/image/boot_header.c"]
-        sources += ["embed/sec/image/boot_ucb.c"]
+        sources += ["embed/sec/image/stm32/boot_header.c"]
+        sources += ["embed/sec/image/stm32/boot_ucb.c"]
         defines += [("USE_BOOT_UCB", "1")]
         features_available.append("boot_ucb")