Kindly i need a help for this, i have a KII-L21 phone model, i flashed a custom rom then wanted to go back to the stock rom, i followed a guide here that mentioned to restore from TWRP, i did so but the simm didn't want to work and i wasn't able to flash TWRP again or unlock the bootloader as the serial no. of the phone changed so it didn't match with the IMEI also the update from the settings didn't install, can some one help please to solve that issue