diff --git a/memory.c b/memory.c
index e49a3155f1..496d39e6c1 100644
--- a/memory.c
+++ b/memory.c
@@ -22,16 +22,16 @@
 #include "memory.h"
 #include "sha2.h"
 
-#define OPTION_BYTES_1 ((uint64_t *)0x1FFFC000)
-#define OPTION_BYTES_2 ((uint64_t *)0x1FFFC008)
+#define FLASH_OPTION_BYTES_1 (*(const uint64_t *)0x1FFFC000)
+#define FLASH_OPTION_BYTES_2 (*(const uint64_t *)0x1FFFC008)
 
 void memory_protect(void)
 {
 #if MEMORY_PROTECT
 	// Reference STM32F205 Flash programming manual revision 5 http://www.st.com/resource/en/programming_manual/cd00233952.pdf
 	// Section 2.6 Option bytes
-	//                     set RDP level 2                   WRP for sectors 0 and 1      flash option control register matches
-	if ((((*OPTION_BYTES_1) & 0xFFEC) == 0xCCEC) && (((*OPTION_BYTES_2) & 0xFFF) == 0xFFC) && (FLASH_OPTCR == 0x0FFCCCED)) {
+	//                     set RDP level 2                   WRP for sectors 0 and 1                  flash option control register matches
+	if (((FLASH_OPTION_BYTES_1 & 0xFFEC) == 0xCCEC) && ((FLASH_OPTION_BYTES_2 & 0xFFF) == 0xFFC) && ((FLASH_OPTCR & 0x0FFFFFEC) == 0x0FFCCCED)) {
 		return; // already set up correctly - bail out
 	}
 	flash_unlock_option_bytes();