trezorhal: add flash_set_option_bytes function

micropython/trezorhal/flash.c

@@ -21,3 +21,37 @@ void FLASH_IRQHandler(void) {
     // This call the storage IRQ handler, to check if the flash cache needs flushing
     // storage_irq_handler();
 }
+
+#define WANTED_WRP (OB_WRP_SECTOR_0 | OB_WRP_SECTOR_1)
+#define WANTED_RDP (OB_RDP_LEVEL_2)
+#define WANTED_BOR (OB_BOR_LEVEL3)
+
+void flash_set_option_bytes(void)
+{
+    FLASH_OBProgramInitTypeDef opts;
+
+    HAL_FLASHEx_OBGetConfig(&opts);
+
+    opts.OptionType = 0;
+
+    if (opts.WRPSector != WANTED_WRP) {
+        opts.OptionType = OPTIONBYTE_WRP;
+        opts.WRPState = OB_WRPSTATE_ENABLE;
+        opts.WRPSector = WANTED_WRP;
+        opts.Banks = FLASH_BANK_1;
+    }
+
+    if (opts.RDPLevel != WANTED_RDP) {
+        opts.OptionType = OPTIONBYTE_RDP;
+        opts.RDPLevel = WANTED_RDP;
+    }
+
+    if (opts.BORLevel != WANTED_BOR) {
+        opts.OptionType = OPTIONBYTE_BOR;
+        opts.BORLevel = WANTED_BOR;
+    }
+
+    if (opts.OptionType != 0) {
+        HAL_FLASHEx_OBProgram(&opts);
+    }
+}

micropython/trezorhal/flash.h

@@ -3,4 +3,6 @@
 
 int flash_init(void);
 
+void flash_set_option_bytes(void);
+
 #endif