Just get lucky with the timing :) Like a QTE but without the prompt, that was the main problem. But as programming was done in parts (firmware, PPM (like Win32 resources), content (FAT32 image of storage) it depended on which part was corrupted.
Edit: some people had success on 50th attempt[1], talk about perseverance ;)
Edit: some people had success on 50th attempt[1], talk about perseverance ;)
[1] http://nokiahacking.pl/naprawianie-niewlaczajacego-sie-telef...