This issue is weird and random.
I tested yesterday after flashing to turn airplane on/off = bluetooth not working, had to reboot.
Airplane overnight, turned airplane off = bluetooth ok all day.
Tested now (same as yesterday) to turn airplane on/off = bluetooth ok.
Still have the bluetooth-issue apparently, randomly it doesn't work after switching to/from airplane mode and needs a reboot when not turning on after coming from airplane mode. It's an irritating issue.
I didn't have gps.conf after flash of 8.8.16 so put it there myself.
Only bluetooth issue is that it doesn't come on again after airplane mode.
Don't know if you will get the same issue, but GPS is easy fix as per my previous post.
It probably is different from model to model.
The issue with bluetooth not working after airplane mode is not such a big deal for me, but nice when it's fixed. Got no issues with sensors.
More irritating is that gps.conf is missing so I have to put it there myself. Can't believe that persist includes gps.conf or does it?