removing tmobile os and reinstalling att os?

[jeremyhass]

HI guys I have a tmobile 8120 I bought it to use on ATT network, I know I can get unlock code for it to make it work, but i wanted to get rid of the T-mobile OS and install the ATT OS and I have tryed over and over, I use theJL_CNMDER and wipe the phone and I download the ATT OS and install it to my computer then with the phone displaying 507 install the ATT OS and It keeps booting up after all the time wait the T-MObile software keeps coming back, I did delete the vendor file. so you guys have any suggestions? thanks

[jsconyers]

You cannot legally remove the T-mobile splash screen when the device boots. I assume that's what you're referring to. Changing the OS will not change that screen.

Welcome to the forums.

[jeremyhass]

yeah I see that , but I install my sim card and says invaild sim card?thats the issue i`m having.

[jsconyers]

Is your device unlocked? If not, another carrier's SIM will not work. Changing OS's will not make another carrier's SIM work in your device. You need to have the device unlocked in order to use it on another carrier's network.

[jeremyhass]

ok you just anwsered my question , I thought installing the OS would allow you to use a ATT sim card, Thanks for all you help, where is the best place to get a unlock on the net? I know I will have to pay, any suggetions?thanks

[jsconyers]

I would recommend a platinum sponsor of this site. HorizonWirelessOnline.com - Horizon Wireless, The World’s Cellular Repair Center ß (http://www.horizonwirelessonline.com)

[jeremyhass]

sweet thanks for all you help(y)