diff --git a/recipes-apps/sysmocom-backup-data/files/sysmocom-backup-data b/recipes-apps/sysmocom-backup-data/files/sysmocom-backup-data
index 94eeb12..d78e458 100755
--- a/recipes-apps/sysmocom-backup-data/files/sysmocom-backup-data
+++ b/recipes-apps/sysmocom-backup-data/files/sysmocom-backup-data
@@ -16,6 +16,31 @@ fi
 
 DATE=`date +%Y%m%d`
 
+# Called for a file. Compare with the content in /ro-root
+# if this file has been modified and only take it then. In
+# case the file is not present it in /ro-root it will be
+# added to the backup set
+backup_file() {
+	cmp -s /$2 /ro-root/$2
+	if [ $? -ne 0 ]; then
+		echo "Adding $2"
+		tar -rf $1 --transform='s,^,content/,' -C / $2
+	fi
+}
+
+# Check if this is a file, otherwise descend
+handle_file() {
+	if [ -f "/$2" -a -e "/$2" ]; then
+		backup_file $1 $2
+	fi
+	if [ -d "/$2" -a -e "/$2" ]; then
+		for file in /$2/*;
+		do
+			# Construct to have no leading /
+			handle_file $1 $2/`basename $file`
+		done
+	fi
+}
 
 do_backup_files() {
 	BACKUP_FILE="/data/sysmocom-backup_$DATE.tar"
@@ -32,24 +57,22 @@ do_backup_files() {
 	# 2. Add all the files... we need
 	for file in $FILES;
 	do
-		if [ -e "/$file" ]; then
-			tar -rf $BACKUP_FILE --transform='s,^,content/,' -C / $file
-		fi
+		handle_file $BACKUP_FILE $file
 	done
 
-	# 3. Generate more information
-	NAME="/tmp/backup.$RANDOM"
+	# 4. Generate more information
+	NAME="/tmp/backup.$$"
 	mkdir $NAME
 	opkg list_installed > $NAME/installed_packages
 	/sbin/ifconfig | grep HWaddr | cut -d ' ' -f 11 > $NAME/mac_addr
 
-	# 4. Add the more information
+	# 5. Add the more information
 	tar -rf $BACKUP_FILE --transform='s,^,info/,' -C $NAME installed_packages mac_addr
 
-	# 5. Create stable link
+	# 6. Create stable link
 	ln -sf $BACKUP_FILE /data/sysmocom-backup.tar
 
-	# 6.
+	# 76
 	echo "The backup was stored to $BACKUP_FILE"
 }