I the meanwhile i managed to create ps.fi2 using the fi2encdec on a not encoded diskboot.bin. (Thanx to RaduP)
Now i got blinking the led before boot(), when using ps.fi2 (of course after firm update)
Removing the debug led blinking code, this is the first time, i had the chance to boot the camera with my firmware.
The following happens:
1. I select the firm update.
2. LCD black for 1 second.
3. E51 message appears in the bottom left corner for 4 seconds.
4. Camera switches off.
5. I can switch the camera on without removing the batteries, so it not freezes.