diff --git a/meta/classes/bootimg.bbclass b/meta/classes/bootimg.bbclass
index df3ee73..e65bef7 100644
--- a/meta/classes/bootimg.bbclass
+++ b/meta/classes/bootimg.bbclass
@@ -133,7 +133,7 @@ build_hddimg() {
 		SECTORS=$(expr $SECTORS + $(expr $DIR_SECTORS + $FAT_SECTORS))
 
 		# Determine the final size in blocks accounting for some padding
-		BLOCKS=$(expr $(expr $SECTORS \* 2) + ${BOOTIMG_EXTRA_SPACE})
+		BLOCKS=$(expr $(expr $SECTORS / 2) + ${BOOTIMG_EXTRA_SPACE})
 
 		# Ensure total sectors is an integral number of sectors per
 		# track or mcopy will complain. Sectors are 512 bytes, and we