diff --git a/w39v040c.c b/w39v040c.c
index f631d33..e7a2eb1 100644
--- a/w39v040c.c
+++ b/w39v040c.c
@@ -67,8 +67,8 @@
 		erase_sector_jedec(flash->virtual_memory, i);
 
 	for (i = 0; i < total_size; i++)
-		if (0xff != bios[i]) {
-			printf("ERASE FAILED at 0x%08x!  Expected=0xff, Read=0x%02x\n", i, bios[i]);
+		if (0xff != chip_readb(bios + i)) {
+			printf("ERASE FAILED at 0x%08x!  Expected=0xff, Read=0x%02x\n", i, chip_readb(bios + i));
 			return -1;
 		}