How to fix Error sending MMS on AT&T?

[dannygarced]

Currently I have:

Iphone 4 running 4.2.1 firmware
1.59.00 baseband

I just restored, jailbroke using Green Poison, and installed Cydia. I then unlock using Ultrasnow. When I go to Settings, I have the Carrier Tab. Here are my problems:

Sometimes I get Cellular Data could not be activated
Everything in networks is turned on, Im not using Wifi only 3G
I cannot send MMS pictures, it goes 90% then fails
If I turn Airplane Mode on then Off, the carrier tabs disappears completely and need to turn the phone off. ( Not a problem though)

* I want to be able to have the phone unlocked but keep using it on AT&T for the moment, as I'm selling in in a month or so, and want to be able to sell it as unlocked, but without loosing features as MMS. I've read for fixes for this problem on T-Mobile, but I need a fix for AT&T. Yesterday I did the same process but I removed and reinstalled UltraSnow and then the carrier tab disappeared completely and had to restore again today for it to show up again. I'm currently having the same problem, no MMS on AT&T. Any suggestions to fix this, thank you.

[daytonaviolet]

i had the same problem when using my ultrasnow 1.1 4.0 1.59 with a globe sim card. i had to manually input the apn settings for globe. your case would be to use the carrier file which ATT provides.

Currently I have:

Iphone 4 running 4.2.1 firmware
1.59.00 baseband

I just restored, jailbroke using Green Poison, and installed Cydia. I then unlock using Ultrasnow. When I go to Settings, I have the Carrier Tab. Here are my problems:

Sometimes I get Cellular Data could not be activated
Everything in networks is turned on, Im not using Wifi only 3G
I cannot send MMS pictures, it goes 90% then fails
If I turn Airplane Mode on then Off, the carrier tabs disappears completely and need to turn the phone off. ( Not a problem though)

* I want to be able to have the phone unlocked but keep using it on AT&T for the moment, as I'm selling in in a month or so, and want to be able to sell it as unlocked, but without loosing features as MMS. I've read for fixes for this problem on T-Mobile, but I need a fix for AT&T. Yesterday I did the same process but I removed and reinstalled UltraSnow and then the carrier tab disappeared completely and had to restore again today for it to show up again. I'm currently having the same problem, no MMS on AT&T. Any suggestions to fix this, thank you.