Nits from review

diff --git a/src/handler/lib/get_merkle_preimage.h b/src/handler/lib/get_merkle_preimage.h
index 7b367a0..456d2c0 100644
--- a/src/handler/lib/get_merkle_preimage.h
+++ b/src/handler/lib/get_merkle_preimage.h
@@ -8,7 +8,7 @@
  * The hash is still verified over the full preimage (including the prefix byte).
  *
  * In this flow, the HWW sends a CCMD_GET_PREIMAGE command with a SHA256 hash.
- * The client must respond with the preimage (at most 254 bytes), prefixed by its length.
+ * The client must respond with the preimage, prefixed by its length.
  * The flow fails with SW_WRONG_DATA_LENGTH if the response is too short; it will fail with
  * SW_INCORRECT_DATA if the computed hash does not match.
  *
diff --git a/unit-tests/libs/cx_hash_mock.c b/unit-tests/libs/cx_hash_mock.c
index 8ef68a7..3a06782 100644
--- a/unit-tests/libs/cx_hash_mock.c
+++ b/unit-tests/libs/cx_hash_mock.c
@@ -71,7 +71,8 @@ int cx_hash_sha256(const unsigned char *in,
                    unsigned int in_len,
                    unsigned char *out,
                    unsigned int out_len) {
-    (void) out_len;
+    assert(out != NULL);
+    assert(out_len >= CX_SHA256_SIZE);
     calc_sha_256(out, in, in_len);
     return CX_SHA256_SIZE;
 }
diff --git a/unit-tests/libs/mock_dispatcher.h b/unit-tests/libs/mock_dispatcher.h
index f2b61b5..c4203b3 100644
--- a/unit-tests/libs/mock_dispatcher.h
+++ b/unit-tests/libs/mock_dispatcher.h
@@ -31,7 +31,7 @@
 #define MOCK_MAX_TREES       16
 #define MOCK_MAX_TREE_ELEMS  1024
 #define MOCK_MAX_YIELDED     1024
-#define MOCK_MAX_QUEUE_ELEMS 1024
+#define MOCK_MAX_QUEUE_ELEMS 2048
 #define MOCK_BUF_SIZE        2048
 #define MOCK_MAX_YIELDED_LEN 1024
 
diff --git a/unit-tests/mock_includes/lcx_hash.h b/unit-tests/mock_includes/lcx_hash.h
index 56c50c9..e7f1645 100644
--- a/unit-tests/mock_includes/lcx_hash.h
+++ b/unit-tests/mock_includes/lcx_hash.h
@@ -1,3 +1,4 @@
+#include <stddef.h>
 
 /*******************************************************************************
 *   Ledger Nano S - Secure firmware
diff --git a/unit-tests/mock_includes/lcx_sha256.h b/unit-tests/mock_includes/lcx_sha256.h
index d18dd97..3401f07 100644
--- a/unit-tests/mock_includes/lcx_sha256.h
+++ b/unit-tests/mock_includes/lcx_sha256.h
@@ -1,3 +1,4 @@
+#include <stddef.h>
 
 /*******************************************************************************
 *   Ledger Nano S - Secure firmware
diff --git a/unit-tests/test_get_merkle_leaf_hash.c b/unit-tests/test_get_merkle_leaf_hash.c
index b2854b3..6597ef1 100644
--- a/unit-tests/test_get_merkle_leaf_hash.c
+++ b/unit-tests/test_get_merkle_leaf_hash.c
@@ -349,7 +349,7 @@ static int tamper_corrupt_proof_hash(uint8_t *response_buf,
 
     if (cmd == CCMD_GET_MERKLE_LEAF_PROOF && *response_len > 35) {
         /* Response: <leaf_hash:32> <proof_size:1> <n_proof_elements:1> <proof_hashes...>
-         * Corrupt byte in first proof hash (offset 34) */
+         * Corrupt byte in first proof hash (starting at offset 34) */
         response_buf[35] ^= 0xFF;
     }
     return 0;