I would like to make manual backups of an SD card as a disk image so that it can be easily recreated when needed. I’d like to keep a few versions in case there is a problem I didn’t know about, it can be rolled back.

How can I do this incrementally, or with de-duplication, so that I don’t have to keep full copies of the complete SD card? It’s very big but most of the content won’t be changing much.

It’s for MiyooCFW ROM which is on FAT 32-formatted micro SD card.

Thanks for your help! Also let me know if I am going about the problem in a wrong way.