Mobile network is not working

[HLing]

Hi, i am so close to having a useable mobian-phone (UBPorts-Edition) and i am totally looking forward to. So thanks a lot for your work! :-)
What gives me a headache is getting mobile network to work.
My carrier is o2-germany and i can register for lte,umts and gsm and calls and sms are working so far.
But as soon as i connect to the internet the modem changes to state "unkown". I need to dis- and enable mobile in order to get the modem to register again.
I got the APN-Setup (apn: internet) of the carriers website. 

I tried phosh, modem-manager-gui and mmcli + nmcli. In pureos the modem fails exactly the same.
I am out of ideas for now so any help is appreciated.

I have a similar post on this subject, I have heard that it could be that the firmware on the cellular modem is corrupted. Have you contacted Pine64 about it? I think they should look into it in case it really is a case of faulty hardware.

I have poked at testing this on mobian a few times. I see similar behavior on my Pinephone UBPorts CE. If I test on UBPorts, my data works without issue. I have a feeling this is OS related. Could be modem ROM corruption, but my experience has been similar on a few distros.

Source: I'm doing manual QA on multiple OSes.

Yep, same experience here. In UBPorts the mobile data worked instantly.
The good news. It now works in mobian as well since an update last week. I connect via modem-manager-gui and it connects instantly to 3g and 4G.
Joy!

I am on T-mobile in the US. I've been impressed with Mobian because My Mobian had quite early on had the 4G and signal strength bars on the upper left corner. The mobile data to get online has also worked for some time now.  I only have the slight inconvenience in that the modem seems to turn off ( which would = to "mobile data not working")and I would have to reboot to get it back on.  I usually do
mmcli -m 0 | grep SIM  at which time if i get error: couldn't find modem  I just do sudo reboot and it reboots and i reissue the mmcli -m 0 | grep SIM  then i would get:
SIM     |              dbus path: /org/freedesktop/ModemManager1/SIM/0

at which point I could use the mobile data.  So, I wonder 1) if those who says it doesn't work could have rebooted and gotten it to work.
2) is there a command i can issue to get the modem to work without rebooting? or if there's a setting i need to edit to make the modem stay present more often?

Thank you!