[Frage] FB 6490 Bootloop

I apologize for writing in english but my Germain is so horrible that nobody would understand.

I have a FB 6490 from Vodafone and I tried the ftp procedure to "entbrand' it and I am now stuck in a bootloop :(

I am not managing to login to adam2 anymore. I also tried the reset using a phone but it does not seem to work.
Here is what the box does:
- The LEDs blink once (All)
- power Led blinks fast for 3-4 minutes
- Power LED stays on for 20 seconds

the box reboots.

2 questions:
Must the cable be plugged to login to adam2?
Anything else I can try before I use it for paperweight?

Thank you and sorry for writing in english.