Making a SD Card Backup
You can watch that video: How To Make A BackUp Of Your RetroPie Image
or read:
You can create an sd image of your current sd card with win32diskimager (if you're on windows)
- Plug your sd card into your desktop or laptop computer (you will need a sd card reader for this)
- Open win32diskimager as an administrator (you can right click on it to run as an administrator)
- make sure you have the correct drive letter for your SD card!
- define the file path that you want to save your .img backup as
- Click read to create your backup. (after you've backed this image up if you screw something up later and want to start from this image you can just click write and it will write this sd image back to your sd card.)
- note if you have a 64GB sd card it will create a 64GB backup file even if you don't have it completely filled up. If you don't want a file that large see the next option.
Note: images created this way can only be written to a microSD card of the EXACT same size or bigger. As an example you may not be able to write an image of a 64GB microSD onto another 64GB card. That's because actual real usable space may vary by manufacturer and in some cases even with the same manufacturer.