diff --git a/w39v040c.c b/w39v040c.c
index 37549d7..3a0f430 100644
--- a/w39v040c.c
+++ b/w39v040c.c
@@ -26,22 +26,22 @@
 	volatile uint8_t *bios = flash->virtual_memory;
 	uint8_t id1, id2, lock;
 
-	*(volatile uint8_t *)(bios + 0x5555) = 0xAA;
+	writeb(0xAA, bios + 0x5555);
 	myusec_delay(10);
-	*(volatile uint8_t *)(bios + 0x2AAA) = 0x55;
+	writeb(0x55, bios + 0x2AAA);
 	myusec_delay(10);
-	*(volatile uint8_t *)(bios + 0x5555) = 0x90;
+	writeb(0x90, bios + 0x5555);
 	myusec_delay(10);
 
-	id1 = *(volatile uint8_t *)bios;
-	id2 = *(volatile uint8_t *)(bios + 1);
-	lock = *(volatile uint8_t *)(bios + 0xfff2);
+	id1 = readb(bios);
+	id2 = readb(bios + 1);
+	lock = readb(bios + 0xfff2);
 
-	*(volatile uint8_t *)(bios + 0x5555) = 0xAA;
+	writeb(0xAA, bios + 0x5555);
 	myusec_delay(10);
-	*(volatile uint8_t *)(bios + 0x2AAA) = 0x55;
+	writeb(0x55, bios + 0x2AAA);
 	myusec_delay(10);
-	*(volatile uint8_t *)(bios + 0x5555) = 0xF0;
+	writeb(0xF0, bios + 0x5555);
 	myusec_delay(40);
 
 	printf_debug("%s: id1 0x%02x, id2 0x%02x", __func__, id1, id2);