I have a Mi4i which was rooted and Cyanogen was installed. Suddenly after reboot, the phone stopped booting into the Cyanogen OS.
I tried to flash the Cyanogen again but it did not boot. I flashed the stock ROM, which is MIUI 6 and the phone booted this time. Now I could see that the SIM card was not getting detected. And also IMEI number was showing as invalid.
I then deleted all the partitions and tried to recover the phone by flashing using "MiFlash". This time too the Cyanogen OS didn't boot up. Then I again flashed the stock ROM and this time also MIUI booted up correctly. Still the IMEI was showing as invalid. I don't have any backup of the EFS partition.
I checked the stock ROM flash_all.sh script and could not find any efs partition being written (modemst1, modemst2, fsg). Then from somewhere I got the modemst1, modemst2 and nv_data partition data and I wrote the partitions manually. After writing the EFS partitions Cyanogen booted correctly. But this time the IMEI showed as "012345678901234" and "012345678901235".
As this is a dummy IMEI, the SIM was not getting registered in the network. Tried with QPST RF NV manager tool to write the IMEI which successfully did but with *#06# it still showed Invalid IMEI. Tried with a couple of IMEI flasher and none of them worked.
Also tried to write the IMEI number using AT command (AT+EMGR=1,7,"IMEI1") but the AT command was returning "ERROR"
Please help me to recover my phone. Now I have my phone with MIUI 7 installed and it is working fine except the IMEI issue.
Thanks in advance.