By some… unfortunate user error, I did overwrite my EFS partition with a backup from another phone. Now only one SIM works at a time (in any slot) and IMEIs are set to zero. Is there a way to restore them?
I experienced some hardware issues on my FP3+. Since they were located on the mainboard, exchanging modules was not an option. As I didn’t want to go through the hassle of setting up a new phone from scratch and rather like my FP3, I bought a used phone and planned to simply transfer a TWRP backup.
Unfortunately, I didn’t learn from past experiences and did not make a backup of the new phone before restoring my backup. After booting, I discovered that
- Only one of two SIM is connected to the mobile network. It’s independent of the slot (both slots work if the other one is empty) and of the SIM I insert
- IMEI1 and IMEI2 are both set to zero
Everything else (including mobile data on the usable SIM, texting, Wifi) works, as far as I’ve tested it.
After some research, I narrowed it down to my second mistake: I restored all partitions from my backup, including EFS. As far as I understand it, this means that I flashed unique hardware information from my old phone to my new one, where it is useless and leads to errors.
So far, I’ve tried the following:
- Factory reset and manually installing stock ROM
- Installing LineageOS
- Resetting IMEIs to the ones printed on the back; The IMEIs did get updated, but connectivity didn’t change
- Erasing modemst1, modemst2 and persist; after erasing just modemst1 and modemst2, nothing changed; when erasing persist, too, the phone doesn’t boot anymore and get’s stuck at the loading animation until I restore the partition image from my old phone.
- Changing IMEI using Qualcomm QPST; didn’t get this to work at all (phone not found in QPST)
Is there some other way to restore the lost information? Or is there some other source to the problem that I’m missing entirely?