Here's the thread link:
http://xdaforums.com/showthread.php?t=1449021&page=6
Here's the info you need:
Worked for me. Thanks OP! Followed instructions, added APN, and viola. Now running stock euro gingerbread. For anyone wondering, you MUST add apn for data. Go to wireless and networks>mobile network settings>access point names. Add these settings for AT&T....
Name: AT&T
APN: wap.cingular
Proxy: leave blank
Port: leave blank
Username:WAP@CINGULARGPRS.COM
Password:CINGULAR1
Server: leave blank
MMSC: http://mmsc.cingular.com
MMS Proxy: wireless.cingular.com
MMS Port: 80
MCC:310
MNC:410 (note. this could also be 310, 41 or 15)
APN Type: leave blank
- Thanks to benbowden for posting this in that thread