diff --git a/libflashrom.c b/libflashrom.c
index 19a41cf..c336b8c 100644
--- a/libflashrom.c
+++ b/libflashrom.c
@@ -421,7 +421,7 @@
  *         1 on any other error.
  */
 int flashrom_layout_read_fmap_from_rom(struct flashrom_layout **const layout,
-		struct flashctx *const flashctx, off_t offset, size_t len)
+		struct flashctx *const flashctx, size_t offset, size_t len)
 {
 #ifndef __FLASHROM_LITTLE_ENDIAN__
 	return 3;