boardloader: check flash_option_bytes at start

embed/boardloader/lowlevel.c

@@ -1,10 +1,7 @@
-#include <stdint.h>
-
-#include "common.h"
-#include "rng.h"
-
 #include STM32_HAL_H
 
+#include "lowlevel.h"
+
 #define WANTED_WRP (OB_WRP_SECTOR_0 | OB_WRP_SECTOR_1 | OB_WRP_SECTOR_2)
 #define WANTED_RDP (OB_RDP_LEVEL_2)
 #define WANTED_BOR (OB_BOR_LEVEL3)
@@ -38,3 +35,11 @@ void flash_set_option_bytes(void)
         HAL_FLASHEx_OBProgram(&opts);
     }
 }
+
+bool flash_check_option_bytes(void)
+{
+    return
+        ((FLASH->OPTCR & FLASH_OPTCR_nWRP) == (FLASH_OPTCR_nWRP_0 | FLASH_OPTCR_nWRP_1 | FLASH_OPTCR_nWRP_2)) &&
+        ((FLASH->OPTCR & FLASH_OPTCR_RDP) == FLASH_OPTCR_RDP_2) &&
+        ((FLASH->OPTCR & FLASH_OPTCR_BOR_LEV) == (FLASH_OPTCR_BOR_LEV_0 | FLASH_OPTCR_BOR_LEV_1));
+}

embed/boardloader/lowlevel.h

@@ -1,6 +1,9 @@
 #ifndef __BOARDLOADER_LOWLEVEL_H__
 #define __BOARDLOADER_LOWLEVEL_H__
 
+#include <stdbool.h>
+
 void flash_set_option_bytes(void);
+bool flash_check_option_bytes(void);
 
 #endif

embed/boardloader/main.c

@@ -125,6 +125,10 @@ int main(void)
 
 #if PRODUCTION
     flash_set_option_bytes();
+    if (!flash_check_option_bytes()) {
+        // TODO: erase storage
+        ensure(0, "wrong option bytes");
+    }
 #endif
 
     clear_otg_hs_memory();