Replicant

Sometimes the data on the EFS is corrupted.

In many online guides to restore it rely on proprietary software and/or rely on the EFS being not completely destroyed.

On some devices like the Galaxy S, it's easy to completely destroy the EFS as, during the installation there is a process of converting the partition from BML (a nonstandard block layer used on the Galaxy S) to MTD.

As we still want to support such devices in libsamsung-ipc (but not in Replicant) and that it would be way better to have a robust way of recovering the EFS, it is a good idea to have a way of completely reconstructing it, assuming that the users know their IMEI.

The IMEI that can usually be found under the battery. Cellular network operators also have it, so it may also be possible to recover it through them.

For newer devices, many users probably didn't backup their EFS, as many probably installed Replicant before the BackupTheEFS page existed.

We also have no information on what vendors selling devices with Replicant pre-installed, or people doing install parties do to cope with that.

edit1: Also add XMM626 in this bugreport.