- Nov 29, 2021
您好，很高兴看到您的回复，但我是按照您的步骤操作的。解锁过程中，重启后系统中没有出现OEM按钮。你能帮我做一个更详细的操作步骤吗？Ok so after three months I turned my mind back to this topic again. And yes, I struggled for a couple of hours overnight last night and got the ATT T727A flashed with Lineage. There are a few tricks: First, the USC R4 firmware can be flashed, with the modified version (3B) of Odin, which bypasses the SHA256 error check; Second, when the USC R4 firmware (latest for now is Mar 2021 version, Android 10) is flashed, the start logo changes from slick ATT to full screen big fat US Cellular. Need to wait for a few minutes and let it do its work. Through this flash, user data will not be lost. Third, the USC R4 version does have OEM Unlock automatically present and all it needs is to flip the switch, then go to download mode to unlock the bootloader. This will erase the user data. Fourth, from then on it's all standard procedures to flash any third party roms like LineageOS with MicroG pursuant to their instructions. Four hours work made a good result, and the cellular data is usable without problem.
PS: the concept of timed OEM unlock switch (a week after factory reset) is wrong. It's non-existent so do not waste time on it. Just straigntly flash the USC R4 Version. To flash other roms like Lineage, it would be better to download the Odin with their specified version to prevent hiccups.
Translated by GT: Hello, I am glad to see your reply, but I followed your steps. During the unlocking process, there is no OEM button in the system after restarting. Can you help me do a more detailed procedure?
Last edited by a moderator: