diff --git a/CommonInstaller b/CommonInstaller
index 14d6756..f0cd860 100644
--- a/CommonInstaller
+++ b/CommonInstaller
@@ -525,7 +525,7 @@ magisk_install_preinst () {
 	fi
 
 	if [ -f ${RESTORE_PATH}/system/framework/services.jar ]; then
-		if [ -f /data/adb/.nanodroid-patcher -o /data/adb/NanoDroid_Patched ]; then
+		if [ -f /data/adb/.nanodroid-patcher -o -f /data/adb/NanoDroid_Patched ]; then
 			ui_print " << backing up patched services.jar"
 			cp ${RESTORE_PATH}/system/framework/services.jar \
 				${TMPDIR}/services.jar
@@ -535,7 +535,7 @@ magisk_install_preinst () {
 			ui_print " "
 			rm -f ${RESTORE_PATH}/system/framework/services.jar
 		fi
-	elif [ -f /data/adb/.nanodroid-patcher -o /data/adb/NanoDroid_Patched ]; then
+	elif [ -f /data/adb/.nanodroid-patcher -o -f /data/adb/NanoDroid_Patched ]; then
 		ui_print " "
 		ui_print " ++ /data/adb/NanoDroid_Patched exists, but"
 		ui_print " ++ ${RESTORE_PATH}/system/framework/services.jar"