New glass/digitizer not recognized

Hej guys,

i have changed a cracked Lumia 920 glass/with digitizer, but the digitizer doesn´t work.

I´ve checked the connector but it was perfectly in place, so i hard reset it with no result either.

The phone is the rm-821 version according to seidea´s list and the new glass is labeled as at&t (bought the phone in europe).

Could the firmware be the problem? I can imagine it is not supporting the digitizer and read somewhere Lumia Amber and later Versions are the problem.

Can i use Nokia Software Update to get Lumia Black back on the phone?

hope you can help me out!

cheers,

Lukas