diff --git a/meta/classes/image_types.bbclass b/meta/classes/image_types.bbclass
index f11a7ed..f23c1f5 100644
--- a/meta/classes/image_types.bbclass
+++ b/meta/classes/image_types.bbclass
@@ -63,7 +63,7 @@ IMAGE_CMD_ubi () {
 IMAGE_CMD_ubifs = "mkfs.ubifs -r ${IMAGE_ROOTFS} -o ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.ubifs.img ${MKUBIFS_ARGS}"
 
 EXTRA_IMAGECMD = ""
-EXTRA_IMAGECMD_jffs2 = "--pad --little-endian --eraseblock=0x40000"
+EXTRA_IMAGECMD_jffs2 ?= "--pad --little-endian --eraseblock=0x40000"
 EXTRA_IMAGECMD_yaffs2 = "1"
 # Change these if you want default genext2fs behavior (i.e. create minimal inode number)
 EXTRA_IMAGECMD_ext2 ?= "-i 8192"