--- a/include/linux/bcm963xx_tag.h
+++ b/include/linux/bcm963xx_tag.h
@@ -92,8 +92,10 @@ struct bcm_tag {
 	__u32 rootfs_crc;
 	/* 224-227: CRC32 of kernel partition */
 	__u32 kernel_crc;
-	/* 228-235: Unused at present */
-	char reserved1[8];
+	/* 228-231: Unused at present */
+	char reserved1[4];
+	/* 222-235: Openwrt: real rootfs length */
+	__u32 real_rootfs_length;
 	/* 236-239: CRC32 of header excluding last 20 bytes */
 	__u32 header_crc;
 	/* 240-255: Unused at present */
--- a/drivers/mtd/parsers/parser_imagetag.c
+++ b/drivers/mtd/parsers/parser_imagetag.c
@@ -137,7 +137,8 @@ static int bcm963xx_parse_imagetag_parti
 		} else {
 			/* OpenWrt layout */
 			rootfsaddr = kerneladdr + kernellen;
-			rootfslen = spareaddr - rootfsaddr;
+			rootfslen = buf->real_rootfs_length;
+			spareaddr = rootfsaddr + rootfslen;
 		}
 	} else {
 		goto out;
