When I was getting my phone setup for LineageOS, I accideantly followed the instructions while a version behind. I managed to use a dump of partition back-ups to get back to a working system and then successfully get Lineage installed, but ever since I can't get cell service with my SIM. It just is stuck forever searching for a network. My IMEI appears to be intact, but I don't know. I saw someone else around that time who solved this problem but can't find their thread anymore.