unlock LG Thrill can't use tmobile mobile internet need help

[matdog56]

I just unlocked my LG Thrill from ATT to T-Mobile. I have call t-mobile and have the actual APN settings written down and I change my APN setting when the T-Mobile tech on the phone with me. it just wont let me select T-Mobile after I add the new APN and I can't delet the old ATT APN so now I can't use t-mobile's mobile internet but only the voice and wifi works. so any one who know how to fix this problem PLEASE HELP......
Thank you

[dlamber7]

I'm not too familiar with at&t phones, but from what I'm told they are pretty locked down in stock. You may need to flash a custom rom to have access to saving a different apn.

Sent from my SCH-I510 using Tapatalk 2

[Djhonlay]

Try to reinstall it.

[Saurus]

I just unlocked my LG Thrill from ATT to T-Mobile. I have call t-mobile and have the actual APN settings written down and I change my APN setting when the T-Mobile tech on the phone with me. it just wont let me select T-Mobile after I add the new APN and I can't delet the old ATT APN so now I can't use t-mobile's mobile internet but only the voice and wifi works. so any one who know how to fix this problem PLEASE HELP......
Thank you

AT&T and T-Mobile USA use different 3G bands. You can not get 3G data speeds with cross-branded phones, but 2G (EDGE) data should work, since that data is carried within the GSM bands. There is no software mod that can enable a phone to use a different band; it appears to be a hardware difference, perhaps different 3G antenna configuration.

But the apn still has to be changed; idk how it is being disallowed. Find and install a custom rom for your phone is the best bet, as dlamber7 suggests.