My phone was originally TPA(panama). I used the *#272*IEMI# code to pull up the preconfig and changed the CSC to TMS(Slovakia T-mobile). This is not working well as the connection to the network is not stable. I tried to use the same 272 code to pull up the menu again but it keeps saying "Connection problem or invalid MMI code". I notice that the phone is connect to 4G but drops to H or E and that message appears. It happens every time. I tried to wipe cache and factory reset. I tried to flash stock firmware from the correct CSC and from other CSC. The flash is successful and the firmware shows in the Software info but CSC does not change and is stuck on TMS. Help!
I am currently on Tmobile US network. I just want to revert it back to TPA since it was better.
EDIT: im reading that android 10 allows for google phone to access these developer menus directly using code rather than running USSD code. I think the USSD code execution and the network is my issue. But i am having issue downgrading to android 10. Keeps giving me bootloader check errors and kernel check errors. I have tried rolling back to the update just before the current update which is still android 11 but different binary. Please help on either issue. direct CSC or downgrading
