diff --git a/m29f400bt.c b/m29f400bt.c
index 40b219c..7d8539f 100644
--- a/m29f400bt.c
+++ b/m29f400bt.c
@@ -64,6 +64,9 @@
 	myusec_delay(10);
 
 	id1 = *(volatile uint8_t *)bios;
+	/* The data sheet says id2 is at (bios + 0x01) and id2 listed in
+	 * flash.h does not match. It should be possible to use JEDEC probe.
+	 */
 	id2 = *(volatile uint8_t *)(bios + 0x02);
 
 	*(volatile uint8_t *)(bios + 0xAAA) = 0xAA;