I just successfully unbricked my Kobo Mini using the image I got from fat265 (again, thank you very much!)
Also, doing that, I changed the S/N written in his image to match my device (using a hex file editor) - the S/N is written in the beginning of the image and is easy to find.
His image was a 4GB one and I have a 2GB card in my Mini, but I just used dd to write as much as I can and repaired the partitions using gparted afterwards.
Before I did that I tried to use an image I got from davidfor, but it didn't work - it was a Touch image.
Anyway, I'm a happy man now, and for other people having a Kobo that doesn't even light its LEDs:
There's always hope!
I still have the image if anyone needs it, but I erased my S/N.
peace!