Adapting via Firmware upload an Annex A modem to Annex B

Hello everyone!

I am in Germany and I would like to replace my German modem router (annex B) with one of the following modems (annex A):

1. Netgear N300 Wireless ADSL2+ Modem Router DGN2200v3 and

2. Netgear DG834G v5 ADSL2+.

After connecting the DGN2200v3 to the telephone network via an adapter, I tried to load the german firmware onto the modem, but it doesn't work.

Can someone please tell me if it is possible to reprogram one of the two modems so that it works with the German telephone network (annex B)?

Thank you in advance,

Caesar

P.S.:

I apologize in advance if my help request is in the wrong place.