If you’re a custom ROM user, or experimented with them before, you probably know that IMEI and some other important stuff of the device gets overwritten and deletes itself.IMEI is like device’s identify; it’s needed so that the country the device is in recognizes the device and lets the simcard work. This guide will show you how to backup them to restore them later so that they won’t get lost.
EFS Backup Guide
TWRP/OFOX/any recovery that has backup feature is required for this process.
- Boot your phone to your recovery(the one you have installed).
- Go to “Backup”(in this case, I’m using TWRP, so I will explain the process according to it).
- Choose “EFS”. If you use MediaTek device, choose nvram, nvdata, nvcfg, protect_f, protect_s
- Rename the backup to something that you will remember (e.g imeibackup) so that you won’t get confused when restoring it.
- Move the backup to somewhere else(its located under /TWRP/backups/devicename/backupname
- Now, do your process(e.g flashing a rom).
- If the IMEI is gone, move the backup file to correct path in device.
- Go to “Restore”.
- Choose the backup that you did it before.
- Choose what partitions to restore, and start restore.
- And voila; your IMEI should be back there in place untouched.
Please keep in mind that instead of only backing up EFS backing up all partitions is highly recommended incase something else also goes wrong. Also, in MediaTek, EFS partition does not exist because it doesn’t use that for storing IMEI. Instead, do the same process but backup these partitions;
- nvcfg
- nvdata
- nvram
- protect_f
- protect_s
In MediaTek the partitions above are responsible for the IMEI. But again as said, full backup is highly recommended instead of only backing up these partitions, anything can go wrong if flashing process was wrong.
