[dogma1138]

It really depends how these things are setup.

Factory resetes that reset the EEPROM basically usually means that the hardcoded values form the ROM/Firmware will be used on the next boot.

However you usually have another tier today which is flash storage which isn’t a mechanism that can be easily reset with a “factory reset” because it involves a file system.

If the bad config files are on the flash you need a factory reset mechanism that basically tells the main firmware or boot loader to recreate the file system on the next boot.

[grishka]

That's how factory reset works on Android — it simply erases the entire /data partition, which is the only one normally mounted read-write. Recovery might subsequently initialize an empty file system there, but bootloader certainly does not. (you're usually able to do a wipe from both)

The OS itself then initializes it all from scratch on the first boot.