hal: add print_screen to Hal Ui

diff --git a/src/rust/bitbox-hal/src/ui.rs b/src/rust/bitbox-hal/src/ui.rs
index ecb55b9..877050e 100644
--- a/src/rust/bitbox-hal/src/ui.rs
+++ b/src/rust/bitbox-hal/src/ui.rs
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use alloc::string::String;
+use core::time::Duration;
 
 pub struct UserAbort;
 
@@ -88,6 +89,10 @@ pub trait Ui {
 
     async fn status(&mut self, title: &str, status_success: bool);
 
+    /// Render a debug/error message directly to the screen.
+    /// If `duration` is zero, the message remains visible indefinitely.
+    fn print_screen(&mut self, duration: Duration, msg: &str);
+
     /// Switches the waiting screen from the lockscreen (as described in
     /// [`crate::system::System::startup`]) to the BitBox logo.
     fn switch_to_logo(&mut self);
diff --git a/src/rust/bitbox02-rust-c/src/lib.rs b/src/rust/bitbox02-rust-c/src/lib.rs
index 7968dd8..0922e9c 100644
--- a/src/rust/bitbox02-rust-c/src/lib.rs
+++ b/src/rust/bitbox02-rust-c/src/lib.rs
@@ -8,6 +8,7 @@ extern crate std;
 
 #[macro_use]
 mod c_alloc;
+extern crate alloc;
 
 #[cfg(feature = "firmware")]
 pub mod async_usb;
@@ -115,7 +116,14 @@ fn panic(info: &core::panic::PanicInfo) -> ! {
     #[cfg(feature = "firmware")]
     ::util::log::log!("{}", info);
     #[cfg(feature = "firmware")]
-    bitbox02_rust::print_screen!(0, "Error: {}", info);
+    {
+        use bitbox_hal::{Hal, Ui};
+
+        let mut hal = crate::HalImpl::new();
+        let msg = alloc::format!("Error: {}", info);
+        hal.ui()
+            .print_screen(core::time::Duration::from_millis(0), &msg);
+    }
     cortex_m::asm::bkpt();
     loop {}
 }
diff --git a/src/rust/bitbox02-rust/src/general.rs b/src/rust/bitbox02-rust/src/general.rs
index 388f8ad..6517268 100644
--- a/src/rust/bitbox02-rust/src/general.rs
+++ b/src/rust/bitbox02-rust/src/general.rs
@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: Apache-2.0
 
-#[macro_use]
-pub mod screen;
+use crate::hal::Ui;
+use core::time::Duration;
 
 /// displays the input error message on the screen and enters
 /// an infinite loop.
 #[allow(clippy::empty_loop)]
-pub fn abort(err: &str) -> ! {
-    print_screen!(0, "Error: {}", err);
+pub fn abort(hal: &mut impl crate::hal::Hal, err: &str) -> ! {
+    hal.ui()
+        .print_screen(Duration::from_millis(0), &format!("Error: {}", err));
     loop {}
 }
diff --git a/src/rust/bitbox02-rust/src/general/screen.rs b/src/rust/bitbox02-rust/src/general/screen.rs
deleted file mode 100644
index e3e00b3..0000000
--- a/src/rust/bitbox02-rust/src/general/screen.rs
+++ /dev/null
@@ -1,32 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-
-use core::time::Duration;
-
-use bitbox02::{delay, screen_clear, ug_font_select_9x9, ug_put_string, ug_send_buffer};
-
-pub fn print_debug_internal(duration: Duration, msg: &str) {
-    screen_clear();
-    ug_font_select_9x9();
-    ug_put_string(0, 0, msg, false);
-    ug_send_buffer();
-    delay(duration);
-}
-
-/// This is a convenience macro for printing to the screen.
-///
-/// Example usage:
-///
-/// ```no_run
-/// # #[macro_use] extern crate bitbox02_rust; fn main() {
-/// let my_str = "abc";
-/// print_screen!(1000, "{}", &my_str);
-/// # }
-/// ```
-#[macro_export]
-macro_rules! print_screen {
-    ($duration:expr, $($arg:tt)*) => ({
-        extern crate alloc;
-        let duration = core::time::Duration::from_millis($duration);
-        $crate::general::screen::print_debug_internal(duration, &alloc::format!($($arg)*));
-    })
-}
diff --git a/src/rust/bitbox02-rust/src/hal/testing/ui.rs b/src/rust/bitbox02-rust/src/hal/testing/ui.rs
index db58a03..490c1fe 100644
--- a/src/rust/bitbox02-rust/src/hal/testing/ui.rs
+++ b/src/rust/bitbox02-rust/src/hal/testing/ui.rs
@@ -9,6 +9,7 @@ use alloc::boxed::Box;
 use alloc::collections::VecDeque;
 use alloc::string::String;
 use alloc::vec::Vec;
+use core::time::Duration;
 
 #[derive(Debug, Eq, PartialEq, Clone)]
 pub enum Screen {
@@ -30,6 +31,10 @@ pub enum Screen {
         title: String,
         success: bool,
     },
+    PrintScreen {
+        message: String,
+        duration: Duration,
+    },
     ShowMnemonic {
         words: Vec<String>,
     },
@@ -147,6 +152,13 @@ impl Ui for TestingUi<'_> {
         }
     }
 
+    fn print_screen(&mut self, duration: Duration, msg: &str) {
+        self.screens.push(Screen::PrintScreen {
+            message: msg.into(),
+            duration,
+        });
+    }
+
     fn switch_to_logo(&mut self) {}
 
     async fn enter_string(
diff --git a/src/rust/bitbox02-rust/src/lib.rs b/src/rust/bitbox02-rust/src/lib.rs
index fe6f863..105b7a8 100644
--- a/src/rust/bitbox02-rust/src/lib.rs
+++ b/src/rust/bitbox02-rust/src/lib.rs
@@ -12,14 +12,13 @@ mod pb_backup {
     include!("./shiftcrypto.bitbox02.backups.rs");
 }
 
-#[macro_use]
-pub mod general;
 pub mod async_usb;
 pub mod attestation;
 pub mod backup;
 mod bip32;
 pub mod bip39;
 pub mod communication_mode;
+pub mod general;
 pub mod hal;
 pub mod hash;
 pub mod hww;
diff --git a/src/rust/bitbox02-rust/src/reset.rs b/src/rust/bitbox02-rust/src/reset.rs
index e63b866..670767d 100644
--- a/src/rust/bitbox02-rust/src/reset.rs
+++ b/src/rust/bitbox02-rust/src/reset.rs
@@ -29,7 +29,7 @@ pub(crate) async fn reset(hal: &mut impl crate::hal::Hal, status: bool) {
         }
     }
     if !reset_ok {
-        abort("Could not reset secure chip.");
+        abort(hal, "Could not reset secure chip.");
     }
 
     #[cfg(feature = "app-u2f")]
@@ -42,12 +42,12 @@ pub(crate) async fn reset(hal: &mut impl crate::hal::Hal, status: bool) {
             }
         }
         if !u2f_ok {
-            abort("Could not initialize U2F counter.");
+            abort(hal, "Could not initialize U2F counter.");
         }
     }
 
     if hal.memory().reset_hww().is_err() {
-        abort("Could not reset memory.");
+        abort(hal, "Could not reset memory.");
     }
 
     // Disable SmartEEPROM so it will be erased on next reboot.
diff --git a/src/rust/bitbox02-rust/src/workflow/unlock.rs b/src/rust/bitbox02-rust/src/workflow/unlock.rs
index 8683d53..813c8bd 100644
--- a/src/rust/bitbox02-rust/src/workflow/unlock.rs
+++ b/src/rust/bitbox02-rust/src/workflow/unlock.rs
@@ -156,34 +156,37 @@ pub async fn unlock_bip39(hal: &mut impl crate::hal::Hal, seed: &[u8]) {
         }
     }
 
-    let crate::hal::HalSubsystems {
-        ui,
-        random,
-        securechip,
-        memory,
-        ..
-    } = hal.as_mut();
-    let mut keystore_hal = crate::keystore::KeystoreHalImpl::new(memory, random, securechip);
-
-    let ((), result) = futures_lite::future::zip(
-        ui.unlock_animation(),
-        crate::keystore::unlock_bip39(
-            &mut keystore_hal,
-            seed,
-            &mnemonic_passphrase,
-            // for the simulator, we don't yield at all, otherwise unlock becomes very slow in the
-            // simulator.
-            #[cfg(any(feature = "c-unit-testing", feature = "simulator-graphical"))]
-            async || {},
-            // we yield every time to keep the processing time per iteration to a minimum.
-            #[cfg(not(any(feature = "c-unit-testing", feature = "simulator-graphical")))]
-            futures_lite::future::yield_now,
-        ),
-    )
-    .await;
+    let result = {
+        let crate::hal::HalSubsystems {
+            ui,
+            random,
+            securechip,
+            memory,
+            ..
+        } = hal.as_mut();
+        let mut keystore_hal = crate::keystore::KeystoreHalImpl::new(memory, random, securechip);
+
+        let ((), result) = futures_lite::future::zip(
+            ui.unlock_animation(),
+            crate::keystore::unlock_bip39(
+                &mut keystore_hal,
+                seed,
+                &mnemonic_passphrase,
+                // for the simulator, we don't yield at all, otherwise unlock becomes very slow in the
+                // simulator.
+                #[cfg(any(feature = "c-unit-testing", feature = "simulator-graphical"))]
+                async || {},
+                // we yield every time to keep the processing time per iteration to a minimum.
+                #[cfg(not(any(feature = "c-unit-testing", feature = "simulator-graphical")))]
+                futures_lite::future::yield_now,
+            ),
+        )
+        .await;
+        result
+    };
 
     if result.is_err() {
-        abort("bip39 unlock failed");
+        abort(hal, "bip39 unlock failed");
     }
 }
 
diff --git a/src/rust/bitbox02/src/hal/ui.rs b/src/rust/bitbox02/src/hal/ui.rs
index 93159cb..ac6b72d 100644
--- a/src/rust/bitbox02/src/hal/ui.rs
+++ b/src/rust/bitbox02/src/hal/ui.rs
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use alloc::string::String;
+use core::time::Duration;
 
 use bitbox_hal::Ui;
 use bitbox_hal::ui::{
@@ -129,6 +130,14 @@ impl Ui for BitBox02Ui {
         crate::ui::status(title, status_success).await
     }
 
+    fn print_screen(&mut self, duration: Duration, msg: &str) {
+        crate::screen_clear();
+        crate::ug_font_select_9x9();
+        crate::ug_put_string(0, 0, msg, false);
+        crate::ug_send_buffer();
+        crate::delay(duration);
+    }
+
     #[inline(always)]
     fn switch_to_logo(&mut self) {
         crate::ui::screen_process_waiting_switch_to_logo();