diff --git a/core/embed/trezorhal/stm32u5/mpu.c b/core/embed/trezorhal/stm32u5/mpu.c
index 8baa72449b..01f83f172d 100644
--- a/core/embed/trezorhal/stm32u5/mpu.c
+++ b/core/embed/trezorhal/stm32u5/mpu.c
@@ -154,8 +154,8 @@ static void mpu_set_attributes(void) {
 #endif
 
 #ifdef SYSCALL_DISPATCH
-extern uint32_t _uflash_start;
-extern uint32_t _uflash_end;
+extern uint8_t _uflash_start;
+extern uint8_t _uflash_end;
 #define KERNEL_RAM_U_START (KERNEL_RAM_START + KERNEL_RAM_SIZE)
 #define KERNEL_RAM_U_SIZE KERNEL_U_RAM_SIZE
 #define KERNEL_FLASH_U_START (uint32_t) & _uflash_start
diff --git a/core/embed/trezorhal/stm32u5/secure_aes.c b/core/embed/trezorhal/stm32u5/secure_aes.c
index 036c3958a3..264473ba04 100644
--- a/core/embed/trezorhal/stm32u5/secure_aes.c
+++ b/core/embed/trezorhal/stm32u5/secure_aes.c
@@ -141,8 +141,8 @@ saes_invoke(void) {
   return 0;
 }
 
-extern uint32_t sram_u_start;
-extern uint32_t sram_u_end;
+extern uint8_t sram_u_start;
+extern uint8_t sram_u_end;
 
 secbool unpriv_encrypt(const uint8_t* input, size_t size, uint8_t* output,
                        secure_aes_keysel_t key) {