diff --git a/classes/image_types_tegra.bbclass b/classes/image_types_tegra.bbclass
index e597b1b6..2b555730 100644
--- a/classes/image_types_tegra.bbclass
+++ b/classes/image_types_tegra.bbclass
@@ -57,7 +57,7 @@ RECROOTFSSIZE ?= "314572800"
 
 IMAGE_TEGRAFLASH_FS_TYPE ??= "ext4"
 IMAGE_TEGRAFLASH_ROOTFS ?= "${IMGDEPLOYDIR}/${IMAGE_LINK_NAME}.${IMAGE_TEGRAFLASH_FS_TYPE}"
-TEGRAFLASH_ROOTFS_EXTERNAL = "${@'1' if d.getVar('TNSPEC_BOOTDEV') != 'mmcblk0p1' else '0'}"
+TEGRAFLASH_ROOTFS_EXTERNAL = "${@'1' if d.getVar('TNSPEC_BOOTDEV') != d.getVar('TNSPEC_BOOTDEV_DEFAULT') else '0'}"
 ROOTFS_DEVICE_FOR_INITRD_FLASH = "${@tegra_rootfs_device(d)}"
 TEGRAFLASH_NO_INTERNAL_STORAGE ??= "0"
 OVERLAY_DTB_FILE ??= ""