Originally Posted by Alex C.
You need to flash a radio for your region. Get it from a stock rom for your region.
Thanks for that. The next question is where I can get such a radio? Unfortunately I was too impatient to flash my phone and didn't make a backup. Do I just have to hunt around and hope I can find someone from my region who has made a backup, or is there a better way to find it?
EDIT: looking at shipped-roms.com, there are a few stock radio images, but none which are obviously A810B. I will try the asian radio there, but I don't have high hopes.