If you are using Link2SD like me, most likely you have an ext4 partition on your micro SD card. Windows does not have a native support for ext4. And to make a true backup, you have to preserve the permission and ownership too. That's why I am using a Linux box (VM) and a card reader ($0.99) to create my backups.
Here are the steps,
1. On your Linux box, make sure you are super user (root). Make sure you have mount_dir and backup_dir directories created.
2. mount /dev/sdb2 mount_dir/
3. cp -rp mount_dir/* backup_dir/
4. umount mount_dir
That's it. To restore those files, you just copy them back, with the same -rp parameters. And you can use the same method to restore the files even after you change the partition size. You do not even have to recreate the Link2SD script.
Here are the steps,
1. On your Linux box, make sure you are super user (root). Make sure you have mount_dir and backup_dir directories created.
2. mount /dev/sdb2 mount_dir/
3. cp -rp mount_dir/* backup_dir/
4. umount mount_dir
That's it. To restore those files, you just copy them back, with the same -rp parameters. And you can use the same method to restore the files even after you change the partition size. You do not even have to recreate the Link2SD script.