Hi there.
I just want to update here with a short report about loosing randomly the IMEI on my XZ1 Compact using the IodeOS 5.10 ROM and successfully restoring it via TWRP recovery.
I switched off my phone normally yesterday and when I booted it this morning, I had lost the IMEI again (for the second time, last time this happened in august last year) The symptoms are:
- the SIM card was not detected
- Settings → About Phone → IMEI showed no IMEI anymore
I used the method to fix IMEI again via TWRP recovery as described here.
- Reboot into recovery (If you do not know how to do this, an easy way is: Settings → System → Buttons → Power Menu → Activate Advanced Restart. You can then select reboot into recovery when you open the Power Menu by pressing the power button.
- Advanced → Terminal
- Type two commands:
dd if=/dev/zero of=/dev/block/bootdevice/by-name/modemst1
dd if=/dev/zero of=/dev/block/bootdevice/by-name/modemst2
There was some error message about full memory (see attached screenshot) but I rebooted anyway.
The fix worked. I had cell phone connection again and the IMEI is showing up in settings again. So this works even if you lose your IMEI on a trip and you have no access to a PC to fix it.
Maybe this post can help some people having similar issue. 
