Why won't my Galaxy S3 (verizon SCH-I535) get 3G on ATT ?

[AC Question]

why won't my Galaxy s3 (verizon SCH-I535) get 3G on ATT ?

I only get EDGE data on ATT network. The ATT store confirmed the APN setting are correct. Calls and texts are fine, but data is slow.

 

[Rukbat]

Re: why won't my Galaxy s3 (verizon SCH-I535) get 3G on ATT ?

Turn off wifi. If that fixes it, it may be an AT&T thing. I can't get 4G on a Note 3 without turning it off.

If not, it could be a bad radio or a bad modem (firmware). The modem can be reflashed. (See [Samsung] How to flash Stock ROM via ODIN - you don't want to flash the whole ROM, just the modem file. You can probably find one at AT&T Galaxy S III Android Development - XDA Forums A lot of the developers there have individual files. If no one has posted modems, ask. Someone may. (ALL the AT&T Note 3 modems have been posted in a single post.)