refactor(core): update bootloader from coreapp, using syscalls (and smcalls)

[no changelog]

core/SConscript.firmware

@@ -468,6 +468,7 @@ ALLPATHS = [
         'embed/models',
         'embed/gfx/inc',
         'embed/sys/bsp/inc',
+        'embed/util/bl_check/inc',
         'embed/util/image/inc',
         'embed/util/rsod/inc',
         'embed/util/scm_revision/inc',
@@ -907,6 +908,16 @@ if 'nrf' in FEATURES_AVAILABLE:
             f'embed/models/{TREZOR_MODEL}/trezor-ble.bin',
             )
 
+tools.embed_compressed_binary(
+        obj_program,
+        env,
+        'bootloader',
+        'embed/projects/bootloaders/bootloader.o',
+        f'embed/models/{TREZOR_MODEL}/bootloaders/bootloader_{BOOTLOADER_SUFFIX}.bin',
+        'firmware',
+        'bootloader',
+        )
+
 env.Depends(obj_program, qstr_generated)
 
 linkerscript_gen = env.Command(

core/SConscript.kernel

@@ -408,16 +408,6 @@ obj_program.extend(
         ' --rename-section .data=.vendorheader,alloc,load,readonly,contents'
         ' $SOURCE $TARGET', ))
 
-tools.embed_compressed_binary(
-        obj_program,
-        env,
-        'bootloader',
-        'embed/projects/bootloaders/bootloader.o',
-        f'embed/models/{TREZOR_MODEL}/bootloaders/bootloader_{BOOTLOADER_SUFFIX}.bin',
-        'kernel',
-        'bootloader',
-        )
-
 if "secmon_layout" in FEATURES_AVAILABLE:
     tools.embed_raw_binary(
             obj_program,

core/SConscript.secmon

@@ -361,10 +361,6 @@ cmake_gen = env.Command(
     action='$MAKECMAKELISTS --sources $ALLSOURCES --dirs $CPPPATH --defs $ALLDEFS',
 )
 
-BOOTLOADER_SUFFIX = TREZOR_MODEL
-if BOOTLOADER_QA:
-    BOOTLOADER_SUFFIX += '_qa'
-
 # select vendor header
 if BOOTLOADER_QA or BOOTLOADER_DEVEL:
     vendor = "dev_DO_NOT_SIGN_signed_dev"
@@ -389,16 +385,6 @@ obj_program.extend(
         ' --rename-section .data=.vendorheader,alloc,load,readonly,contents'
         ' $SOURCE $TARGET', ))
 
-tools.embed_compressed_binary(
-        obj_program,
-        env,
-        'bootloader',
-        'embed/projects/bootloaders/bootloader.o',
-        f'embed/models/{TREZOR_MODEL}/bootloaders/bootloader_{BOOTLOADER_SUFFIX}.bin',
-        'secmon',
-        'bootloader',
-        )
-
 linkerscript_gen = env.Command(
     target='memory.ld',
     source=[f'embed/models/{TREZOR_MODEL}/memory_secmon.ld', env.get('ENV')['LINKER_SCRIPT'].format(target='secmon')],

core/embed/projects/firmware/main.c

@@ -37,13 +37,33 @@
 #include <sys/linker_utils.h>
 #include <sys/systask.h>
 #include <sys/system.h>
+#include <util/bl_check.h>
 #include <util/rsod.h>
 #include "rust_ui_common.h"
 
+#include <blake2s.h>
+
 #ifdef USE_SECP256K1_ZKP
 #include "zkp_context.h"
 #endif
 
+#define CONCAT_NAME_HELPER(prefix, name, suffix) prefix##name##suffix
+#define CONCAT_NAME(name, var) CONCAT_NAME_HELPER(BOOTLOADER_, name, var)
+
+#if BOOTLOADER_QA
+// QA bootloaders
+#define BOOTLOADER_00 CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _QA_00)
+#define BOOTLOADER_FF CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _QA_FF)
+#else
+// normal bootloaders
+#define BOOTLOADER_00 CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _00)
+#define BOOTLOADER_FF CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _FF)
+#endif
+
+// symbols from bootloader.bin => bootloader.o
+extern const void _deflated_bootloader_start;
+extern const void _deflated_bootloader_size;
+
 #ifdef USE_NRF
 #include <io/nrf.h>
 
@@ -62,14 +82,47 @@ int main_func(uint32_t cmd, void *arg) {
 
   bool fading = DISPLAY_JUMP_BEHAVIOR == DISPLAY_RESET_CONTENT;
 
+  bool update_required = false;
+
+#if PRODUCTION || BOOTLOADER_QA
+
+  // replace bootloader with the latest one
+  const uint8_t *data = (const uint8_t *)&_deflated_bootloader_start;
+  const size_t len = (size_t)&_deflated_bootloader_size;
+
+  uint8_t hash_00[] = BOOTLOADER_00;
+  uint8_t hash_FF[] = BOOTLOADER_FF;
+
+  // Check if the boardloader is valid and replace it if not
+  bool bl_update_required =
+      bl_check_check(hash_00, hash_FF, BLAKE2S_DIGEST_LENGTH);
+  update_required = update_required || bl_update_required;
+
+#endif
+
 #ifdef USE_NRF
-  if (nrf_update_required(&nrf_app_start, (size_t)&nrf_app_size)) {
+  bool nrf_update_required_ =
+      nrf_update_required(&nrf_app_start, (size_t)&nrf_app_size);
+  update_required = update_required || nrf_update_required_;
+#endif
+
+  if (update_required) {
     screen_update();
-    nrf_update(&nrf_app_start, (size_t)&nrf_app_size);
     fading = true;
+
+#if PRODUCTION || BOOTLOADER_QA
+    if (bl_update_required) {
+      bl_check_replace(data, len);
     }
 #endif
 
+#ifdef USE_NRF
+    if (nrf_update_required_) {
+      nrf_update(&nrf_app_start, (size_t)&nrf_app_size);
+    }
+#endif
+  }
+
   screen_boot_stage_2(fading);
 
 #ifdef USE_SECP256K1_ZKP

core/embed/projects/kernel/main.c

@@ -157,9 +157,6 @@ void drivers_init() {
   check_oem_keys();
 #endif
 
-#if PRODUCTION || BOOTLOADER_QA
-  check_and_replace_bootloader();
-#endif
 #endif
 
 #ifdef USE_BUTTON

core/embed/projects/secmon/main.c

@@ -77,10 +77,6 @@ static void drivers_init(void) {
   check_oem_keys();
 #endif
 
-#if PRODUCTION || BOOTLOADER_QA
-  check_and_replace_bootloader();
-#endif
-
 #ifdef USE_OPTIGA
   optiga_init_and_configure();
 #endif

core/embed/rust/src/ui/layout_bolt/mod.rs

@@ -80,14 +80,7 @@ impl CommonUI for UIBolt {
         show(&mut frame, fade_in);
     }
 
-    fn screen_update() {
+    fn screen_update() {}
-        let mut frame = ErrorScreen::new(
-            "Update".into(),
-            "Finishing firmware update".into(),
-            "Do not turn off your Trezor".into(),
-        );
-        show(&mut frame, true);
-    }
 
     #[cfg(feature = "ui_debug_overlay")]
     fn render_debug_overlay<'s>(_target: &mut impl shape::Renderer<'s>, _info: DebugOverlay) {

core/embed/rust/src/ui/layout_caesar/mod.rs

@@ -38,9 +38,7 @@ impl CommonUI for UICaesar {
         show(&mut frame, fade_in);
     }
 
-    fn screen_update() {
+    fn screen_update() {}
-        unimplemented!()
-    }
 
     #[cfg(feature = "ui_debug_overlay")]
     fn render_debug_overlay<'s>(_target: &mut impl shape::Renderer<'s>, _info: DebugOverlay) {

core/embed/rust/src/ui/layout_delizia/mod.rs

@@ -86,9 +86,7 @@ impl CommonUI for UIDelizia {
         show(&mut frame, fade_in);
     }
 
-    fn screen_update() {
+    fn screen_update() {}
-        unimplemented!()
-    }
 
     #[cfg(feature = "ui_debug_overlay")]
     fn render_debug_overlay<'s>(target: &mut impl shape::Renderer<'s>, info: DebugOverlay) {

core/embed/sys/linker/stm32f4/firmware.ld

@@ -53,6 +53,8 @@ SECTIONS {
     . = ALIGN(4);
     *(.rodata*);
     . = ALIGN(4);
+    KEEP(*(.bootloader));
+    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH AT>FLASH
 

core/embed/sys/linker/stm32f4/kernel.ld

@@ -44,9 +44,6 @@ SECTIONS {
     *(.text*);
     . = ALIGN(4);
     *(.rodata*);
-    . = ALIGN(4);
-    KEEP(*(.bootloader));
-    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH AT>FLASH
 

core/embed/sys/linker/stm32u58/firmware.ld

@@ -44,6 +44,9 @@ SECTIONS {
     *(.text*);
     . = ALIGN(4);
     *(.rodata*);
+    . = ALIGN(4);
+    KEEP(*(.bootloader));
+    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH AT>FLASH
 

core/embed/sys/linker/stm32u58/kernel.ld

@@ -45,9 +45,6 @@ SECTIONS {
     *(.text*);
     . = ALIGN(4);
     *(.rodata*);
-    . = ALIGN(4);
-    KEEP(*(.bootloader));
-    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH AT>FLASH
 

core/embed/sys/linker/stm32u5g/firmware.ld

@@ -49,6 +49,9 @@ SECTIONS {
     . = ALIGN(4);
     KEEP(*(.nrf_app));
     *(.nrf_app*);
+    . = ALIGN(4);
+    KEEP(*(.bootloader));
+    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH AT>FLASH
 

core/embed/sys/linker/stm32u5g/kernel.ld

@@ -49,9 +49,6 @@ SECTIONS {
     *(.text*);
     . = ALIGN(4);
     *(.rodata*);
-    . = ALIGN(4);
-    KEEP(*(.bootloader));
-    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH AT>FLASH
 

core/embed/sys/linker/stm32u5g/secmon.ld

@@ -55,9 +55,6 @@ SECTIONS {
     *(.text*);
     . = ALIGN(4);
     *(.rodata*);
-    . = ALIGN(4);
-    KEEP(*(.bootloader));
-    *(.bootloader*);
     . = ALIGN(512);
   } >FLASH
 

core/embed/sys/smcall/stm32/smcall_dispatch.c

@@ -49,6 +49,8 @@
 #include <sec/secret.h>
 #endif
 
+#include <util/bl_check.h>
+
 #include "smcall_numbers.h"
 #include "smcall_probe.h"
 #include "smcall_verifiers.h"
@@ -68,6 +70,19 @@ __attribute((no_stack_protector)) void smcall_handler(uint32_t *args,
       bootargs_get_args__verified(boot_args);
     } break;
 
+    case SMCALL_BL_CHECK_CHECK: {
+      const uint8_t *hash_00 = (const uint8_t *)args[0];
+      const uint8_t *hash_FF = (const uint8_t *)args[1];
+      size_t hash_len = args[2];
+      args[0] = bl_check_check__verified(hash_00, hash_FF, hash_len);
+    } break;
+
+    case SMCALL_BL_CHECK_REPLACE: {
+      const uint8_t *data = (const uint8_t *)args[0];
+      size_t len = args[1];
+      bl_check_replace__verified(data, len);
+    } break;
+
     case SMCALL_GET_BOARD_NAME: {
       args[0] = get_board_name();
     } break;

core/embed/sys/smcall/stm32/smcall_numbers.h

@@ -33,6 +33,9 @@ typedef enum {
   SMCALL_BOOTARGS_SET = 1,
   SMCALL_BOOTARGS_GET_ARGS,
 
+  SMCALL_BL_CHECK_CHECK,
+  SMCALL_BL_CHECK_REPLACE,
+
   SMCALL_REBOOT_DEVICE,
   SMCALL_REBOOT_TO_BOOTLOADER,
   SMCALL_REBOOT_AND_UPGRADE,

core/embed/sys/smcall/stm32/smcall_stubs.c

@@ -35,6 +35,19 @@ void bootargs_set(boot_command_t command, const void *args, size_t args_size) {
 void bootargs_get_args(boot_args_t *args) {
   smcall_invoke1((uint32_t)args, SMCALL_BOOTARGS_GET_ARGS);
 }
+// =============================================================================
+// bl_check.h
+// =============================================================================
+
+bool bl_check_check(const uint8_t *hash_00, const uint8_t *hash_FF,
+                    size_t hash_len) {
+  return (bool)smcall_invoke3((uint32_t)hash_00, (uint32_t)hash_FF,
+                              (uint32_t)hash_len, SMCALL_BL_CHECK_CHECK);
+}
+
+void bl_check_replace(const uint8_t *data, size_t len) {
+  smcall_invoke2((uint32_t)data, len, SMCALL_BL_CHECK_REPLACE);
+}
 
 // =============================================================================
 // board_capabilities.h

core/embed/sys/smcall/stm32/smcall_verifiers.c

@@ -60,6 +60,37 @@ access_violation:
 
 // ---------------------------------------------------------------------
 
+bool bl_check_check__verified(const uint8_t *hash_00, const uint8_t *hash_FF,
+                              size_t hash_len) {
+  if (!probe_read_access(hash_00, hash_len)) {
+    goto access_violation;
+  }
+
+  if (!probe_read_access(hash_FF, hash_len)) {
+    goto access_violation;
+  }
+
+  return bl_check_check(hash_00, hash_FF, hash_len);
+
+access_violation:
+  apptask_access_violation();
+  return false;
+}
+
+void bl_check_replace__verified(const uint8_t *data, size_t len) {
+  if (!probe_read_access(data, len)) {
+    goto access_violation;
+  }
+
+  bl_check_replace(data, len);
+  return;
+
+access_violation:
+  apptask_access_violation();
+}
+
+// ---------------------------------------------------------------------
+
 void reboot_and_upgrade__verified(const uint8_t hash[32]) {
   if (!probe_read_access(hash, 32)) {
     goto access_violation;

core/embed/sys/smcall/stm32/smcall_verifiers.h

@@ -29,6 +29,15 @@ void bootargs_set__verified(boot_command_t command, const void *args,
 
 void bootargs_get_args__verified(boot_args_t *args);
 
+// ---------------------------------------------------------------------
+
+#include <util/bl_check.h>
+
+bool bl_check_check__verified(const uint8_t *hash_00, const uint8_t *hash_FF,
+                              size_t hash_len);
+
+void bl_check_replace__verified(const uint8_t *data, size_t len);
+
 // ---------------------------------------------------------------------
 #include <sys/bootutils.h>
 

core/embed/sys/syscall/inc/sys/syscall_numbers.h

@@ -42,6 +42,9 @@ typedef enum {
 
   SYSCALL_SYSEVENTS_POLL,
 
+  SYSCALL_BL_CHECK_CHECK,
+  SYSCALL_BL_CHECK_REPLACE,
+
   SYSCALL_REBOOT_DEVICE,
   SYSCALL_REBOOT_TO_BOOTLOADER,
   SYSCALL_REBOOT_AND_UPGRADE,

core/embed/sys/syscall/stm32/syscall_dispatch.c

@@ -81,6 +81,10 @@
 #include <io/touch.h>
 #endif
 
+#if PRODUCTION || BOOTLOADER_QA
+#include <util/bl_check.h>
+#endif
+
 #include "syscall_context.h"
 #include "syscall_internal.h"
 #include "syscall_verifiers.h"
@@ -166,6 +170,19 @@ __attribute((no_stack_protector)) void syscall_handler(uint32_t *args,
       }
     } break;
 
+    case SYSCALL_BL_CHECK_CHECK: {
+      const uint8_t *hash_00 = (const uint8_t *)args[0];
+      const uint8_t *hash_FF = (const uint8_t *)args[1];
+      size_t hash_len = args[2];
+      args[0] = bl_check_check__verified(hash_00, hash_FF, hash_len);
+    } break;
+
+    case SYSCALL_BL_CHECK_REPLACE: {
+      const uint8_t *data = (const uint8_t *)args[0];
+      size_t len = args[1];
+      bl_check_replace__verified(data, len);
+    } break;
+
     case SYSCALL_REBOOT_DEVICE: {
       reboot_device();
     } break;

core/embed/sys/syscall/stm32/syscall_stubs.c

@@ -84,6 +84,20 @@ void sysevents_poll(const sysevents_t *awaited, sysevents_t *signalled,
                   SYSCALL_SYSEVENTS_POLL);
 }
 
+// =============================================================================
+// bl_check.h
+// =============================================================================
+
+bool bl_check_check(const uint8_t *hash_00, const uint8_t *hash_FF,
+                    size_t hash_len) {
+  return (bool)syscall_invoke3((uint32_t)hash_00, (uint32_t)hash_FF,
+                               (uint32_t)hash_len, SYSCALL_BL_CHECK_CHECK);
+}
+
+void bl_check_replace(const uint8_t *data, size_t len) {
+  syscall_invoke2((uint32_t)data, len, SYSCALL_BL_CHECK_REPLACE);
+}
+
 // =============================================================================
 // bootutils.h
 // =============================================================================

core/embed/sys/syscall/stm32/syscall_verifiers.c

@@ -64,6 +64,37 @@ access_violation:
 
 // ---------------------------------------------------------------------
 
+bool bl_check_check__verified(const uint8_t *hash_00, const uint8_t *hash_FF,
+                              size_t hash_len) {
+  if (!probe_read_access(hash_00, hash_len)) {
+    goto access_violation;
+  }
+
+  if (!probe_read_access(hash_FF, hash_len)) {
+    goto access_violation;
+  }
+
+  return bl_check_check(hash_00, hash_FF, hash_len);
+
+access_violation:
+  apptask_access_violation();
+  return false;
+};
+
+void bl_check_replace__verified(const uint8_t *data, size_t len) {
+  if (!probe_read_access(data, len)) {
+    goto access_violation;
+  }
+
+  bl_check_replace(data, len);
+  return;
+
+access_violation:
+  apptask_access_violation();
+}
+
+// ---------------------------------------------------------------------
+
 void system_exit__verified(int exit_code) {
   systask_t *task = systask_active();
 

core/embed/sys/syscall/stm32/syscall_verifiers.h

@@ -44,6 +44,14 @@ void system_exit_fatal__verified(const char *message, size_t message_len,
 
 void reboot_and_upgrade__verified(const uint8_t hash[32]);
 
+// ---------------------------------------------------------------------
+
+bool bl_check_check__verified(const uint8_t *hash_00, const uint8_t *hash_FF,
+                              size_t hash_len);
+
+#include <util/bl_check.h>
+void bl_check_replace__verified(const uint8_t *data, size_t len);
+
 // ---------------------------------------------------------------------
 #include <io/display.h>
 

core/embed/util/bl_check/bl_check.c

@@ -30,40 +30,15 @@
 #include "memzero.h"
 #include "uzlib.h"
 
-// symbols from bootloader.bin => bootloader.o
+static secbool hash_match(const uint8_t *hash, const uint8_t *hash_00,
-extern const void _deflated_bootloader_start;
+                          const uint8_t *hash_FF) {
-extern const void _deflated_bootloader_size;
+  if (0 == memcmp(hash, hash_00, BLAKE2S_DIGEST_LENGTH)) return sectrue;
-
+  if (0 == memcmp(hash, hash_FF, BLAKE2S_DIGEST_LENGTH)) return sectrue;
-#define CONCAT_NAME_HELPER(prefix, name, suffix) prefix##name##suffix
-#define CONCAT_NAME(name, var) CONCAT_NAME_HELPER(BOOTLOADER_, name, var)
-
-#if BOOTLOADER_QA
-// QA bootloaders
-#define BOOTLOADER_00 CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _QA_00)
-#define BOOTLOADER_FF CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _QA_FF)
-#else
-// normal bootloaders
-#define BOOTLOADER_00 CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _00)
-#define BOOTLOADER_FF CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _FF)
-#endif
-// clang-format on
-
-#if PRODUCTION || BOOTLOADER_QA
-static secbool latest_bootloader(const uint8_t *hash, int len) {
-  if (len != 32) return secfalse;
-
-  uint8_t hash_00[] = BOOTLOADER_00;
-  uint8_t hash_FF[] = BOOTLOADER_FF;
-
-  if (0 == memcmp(hash, hash_00, 32)) return sectrue;
-  if (0 == memcmp(hash, hash_FF, 32)) return sectrue;
   return secfalse;
 }
-#endif
 
 #define UZLIB_WINDOW_SIZE (1 << 10)
 
-#if PRODUCTION || BOOTLOADER_QA
 static void uzlib_prepare(struct uzlib_uncomp *decomp, uint8_t *window,
                           const void *src, uint32_t srcsize, void *dest,
                           uint32_t destsize) {
@@ -78,12 +53,15 @@ static void uzlib_prepare(struct uzlib_uncomp *decomp, uint8_t *window,
   decomp->dest_limit = decomp->dest + destsize;
   uzlib_uncompress_init(decomp, window, window ? UZLIB_WINDOW_SIZE : 0);
 }
-#endif
 
-void check_and_replace_bootloader(void) {
+bool bl_check_check(const uint8_t *hash_00, const uint8_t *hash_FF,
-#if PRODUCTION || BOOTLOADER_QA
+                    size_t hash_len) {
   mpu_mode_t mode = mpu_reconfig(MPU_MODE_BOOTUPDATE);
 
+  if (hash_len != BLAKE2S_DIGEST_LENGTH) {
+    error_shutdown("Invalid bootloader hash length");
+  }
+
   // compute current bootloader hash
   uint8_t hash[BLAKE2S_DIGEST_LENGTH];
   const uint32_t bl_len = flash_area_get_size(&BOOTLOADER_AREA);
@@ -94,15 +72,21 @@ void check_and_replace_bootloader(void) {
   // ensure(known_bootloader(hash, BLAKE2S_DIGEST_LENGTH), "Unknown bootloader
   // detected");
 
-  // do we have the latest bootloader?
+  // does the bootloader match?
-  if (sectrue == latest_bootloader(hash, BLAKE2S_DIGEST_LENGTH)) {
+  if (sectrue == hash_match(hash, hash_00, hash_FF)) {
     mpu_reconfig(mode);
-    return;
+    return false;
   }
 
-  // replace bootloader with the latest one
+  mpu_reconfig(mode);
-  const uint32_t *data = (const uint32_t *)&_deflated_bootloader_start;
+  return true;
-  const uint32_t len = (const uint32_t)&_deflated_bootloader_size;
+}
+
+void bl_check_replace(const uint8_t *data, size_t len) {
+  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_BOOTUPDATE);
 
   struct uzlib_uncomp decomp = {0};
   uint8_t decomp_window[UZLIB_WINDOW_SIZE] = {0};
@@ -125,6 +109,8 @@ void check_and_replace_bootloader(void) {
   const image_header *current_bld_hdr =
       read_image_header(bl_data, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_MAXSIZE);
 
+  // todo check sig and contents, as data is now coming from outside
+
   // cannot find valid header for current bootloader, something is wrong
   ensure(current_bld_hdr == (const image_header *)bl_data ? sectrue : secfalse,
          "Invalid bootloader header");
@@ -182,7 +168,6 @@ void check_and_replace_bootloader(void) {
   ensure(flash_lock_write(), NULL);
 
   mpu_reconfig(mode);
-#endif
 }
 
 #endif

core/embed/util/bl_check/inc/util/bl_check.h

@@ -17,9 +17,33 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef __BL_CHECK_H__
+#pragma once
-#define __BL_CHECK_H__
 
-void check_and_replace_bootloader(void);
+#include <trezor_types.h>
 
-#endif
+/**
+ * @brief Verify the installed bootloader against expected hashes.
+ *
+ * Calculates the hash of the currently installed bootloader and compares
+ * it against two known-good expected hashes.
+ *
+ * @param hash_00 Pointer to the expected hash for 0x00 padded image.
+ * @param hash_FF Pointer to the expected hash for 0xFF padded image.
+ * @param hash_len         Length of each hash, in bytes.
+ *
+ * @return `true` if the installed bootloader's hash does not match either
+ *         of the expected hashes (indicating it should be replaced),
+ *         `false` if it matches one of them.
+ */
+bool bl_check_check(const uint8_t *hash_00, const uint8_t *hash_FF,
+                    size_t hash_len);
+
+/**
+ * @brief Replace the currently installed bootloader.
+ *
+ * Writes a new bootloader image into flash.
+ *
+ * @param data Pointer to the bootloader image data.
+ * @param len  Size of the bootloader data in bytes.
+ */
+void bl_check_replace(const uint8_t *data, size_t len);