I'm using bleepbloop usb cart, not the transferer.
Also I backed up safely, the problem was in flashing the new sav, which is odd to me.

It crashed again, this time I managed to get the info from the death screen.

Then I reflashed the ROM, not the RAM. It's going well. I'm not going to change anything to see if things are stabilized (in the crash side).

I'm not the expert, but I kinda doubt it's the battery cause everything is ok, i can save and load fine and it didn't erased anything after it managed to get the sav properly. But thinking about it, can the battery get off by traveling with it, even if i don't open it?

You may be having battery issues.
To be on the safe side, change the battery.

This happened to me once when i was using a bleepbloop usb transferrer with a blue EMS cart.

Test your edited saves on an emulator next time and of course dont forget to backup.

lsdjmanager is not THAT good. sometimes it fails exporting files.

I wrote such a big post and then chipmusic ate it. I dunno why. 

Hurried version of the facts: 

I backed up, used the sav in the lsdmanager, changed the order of some songs, saved it, erased the ram and flashed it. I got a blank sav. Then I re-erased., re-flashed and ok. When I went to load it got stuck. I turned off. Turned on, some scrambled data, but loaded fine. I checked the songs in it, all was cool. Started messing with a song then BAM, the crash screen and the lsdj scream of death. I was in such a shock I couldn't write the data it said in the crash screen cause in 20 secs it went flatline (damn wintermute). Then I turned off, turned on and got scrambled nintendo logo (it happened before in this tale but I forgot when). Took off the cart, placed again and it went ok.

I want to ask the s pecialists if this can happen tomorrow when I'm in a gig. I'm fucking scared of it happening again. 

Any ideas of what can be the cause of it? 

Thanks in advance!