Yippie!
So I got it back to work!!!
After trying out several things I just got it back to work. Sort of...

It can save and load again. Works fine.

But the song screen is still totally corrupted. it has empty lines (or blank steps/loops or whatever you want to call it) where I can't write anything. Even copy to next step doesn't really work.
Any Ideas?

Here is a photo (there should be three lines of numbers, but there are only two. (the ones that showing just 11111...)

For those who want to know how I solved the load save problem.
First I tried to reset the memory of nanoloop, with start and select while booting, didn't seem to work really, but set a new tempo.
Then I tried to reset memory with help of my mega memory card. Didn't seem to work fully either.
After that (and a lot of frustration) I figured out that save does work when I put the same note everywhere, with no extra effects/tables. That so saved pattern was also loadable. Others weren't, so I did the same thing on every pattern. And yes, it worked!
Now I can use all patterns again, and can also use all commands on it again, and it still works. So far it's fine and I'm very... very happy!
Now i can use nanoloop for live stuff again...

Only thing that is still totally corrupted is the song screen. Shows empty steps that are not editable. If it stays like that it's ok, but if anyone could help, would be super nice.
And if anyone could help out in finding out which version this is, would be fine as well.

Thanks nordloef and the mist toggles for your help anyway

This happens on all patterns, just tried it out.

Might be very old, it was bought in Germany.
The sticker is peeled of. And the green cart is a little lighter than in the picture.

sounds like one of the very first batches. but green? can you post a picture?

Does this happen on all patterns or just when loading pattern 0?

Hello Friends,

I've got an old nanoloop cart that i used for live gigs years ago. About 3 years ago it started to crash when I was tring to load or save data.
I always thought it was an empty battery that made this problem appear.
So i changed the battery a week ago, but it still crashes when trying to load or save.
Any ideas what i can do to solve the problem?

It's an old (came in a green shell) nanoloop cart. I don't know which version this is exactly. But it has only three channels, so it's an old cartridge.
Would be great if anyone could help. Would be a shame to make this nice cart a waste.

PS: Sorry for my bad english...