Thank you for your reply!
As I said, I was eventually able to save my emunand. No software on PC worked, I've tried quite a few and gave up. Cloning, backup stuff... No result, it either couldn't find my SD or said it was corrupted. So K ended up hacking my 3DS from scratch and gave it another shot using godmode9... And it worked!
The games are beyond saving, but the save files aren't. I'll just backup my cartridges and download the cias again, I'll manage!
I am now full systemnand as well!