Kerlink iFemtoCell- no access via web or ssh

I’ve just tried updating the office Kerlink IoT to the TTN firmware, but since then I can’t access it anymore. I first tried updating it by just plugging in the USB stick with the TTN settings, but that didn’t work. I then proceeded to use the reset procedure
(Power on the system
Press and release the reset buton
Wait between 4 and 10 seconds.
Repeat point 2. and 3. 22 times! )

help please
thanks in ahead

someone?