diff --git a/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh b/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh
index 1036793145..e62eba7ef1 100755
--- a/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh
+++ b/target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh
@@ -6,8 +6,8 @@ platform_do_upgrade() {
 
 	case "$board" in
 	bananapi,bpi-r64)
-		export_bootdevice
-		export_partdevice rootdev 0
+		local rootdev="$(cmdline_get_var root)"
+		rootdev="${rootdev##*/}"
 		case "$rootdev" in
 		mmc*)
 			CI_ROOTDEV="$rootdev"