Call failure on T-Mobile

[fuzzy7k]

This appears to be effecting multiple people, with similar symptoms for at least 5 people that have said they were on t-mobile. In most cases, the call will ring on the receiving end, and as soon as they answer the call is ended. Sometime the call ends immediately, but shows up as a missed call on the receivers phone. Incoming calls never show up at all. It was reported that restarting eg25-manager increases success rate. However, it has gotten so bad here that calls rarely work even after a fresh boot. When logging into the T-Mobile account, the device shows up as a 5G capable router.

It appears to be network induced, as it has affected phones that have not been update since prior to symptom onset.
It would seem that this coincides with either 5G spinning up, or 3G spinning down. The phones here receive no 2G or 3G signal. Symptoms remain if selecting 4G only mode.

I don't figure that it is a firmware issue, but maybe putting the logs here we can get a better idea of what is going on.

These logs are from a fresh boot and failed call attempt.
openqti.log
modemmanager.log
networkmanager.log
eg25-manager.log
dmesg-pinephone.txt
dmesg-modem.txt

Same situation on Mobian & Manjaro. The variables here are too great to make a good list of software versions and combos so I'm focusing on ADSP versions. Some combination for stock or FLOSS firmware with ADSP versions below.

ADSP that has been tried with no success:
30.004.30.004 - shows up as BYOD-ROUTER, 5G capable
30.006.30.006 - shows up as BYOD-ROUTER, 5G capable
01.003.01.003 - shows up as Galaxy S5
01.002.07 - shows up as Galaxy S® III

Update: It seems that the phones do not work on 4G and were probably downgrading to 2G or 3G before those networks were turned off. After speaking with support, they did some stuff on their end and also had me switch back to 2G,3G,4G. After that calls come in on 2G. Calling out still fails on 4G. Switching to 2G, 3G(preferred) allows calling out. It seems that at some point 2G was switched off and why this initially stopped working. Since then, it was turned back on. Who knows for how much time.