okay, I don’t know what I found earlier, but the diagnose, that there is only configuration for tef_o2/cz seemed to be wrong.
All files are apparently there, but it is still not working yet:
$ ls /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/tef_o2/vlvw/de/
mcfg_sw.mbn -lah
-r--r----- 1 system system 45.0K Mar 30 2021 /vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/euro/tef_o2/vlvw/de/mcfg_sw.mbn
$ cat /vendor/oem/modem-config/S77.2/modem.conf
mcfg_sw/generic/euro/tef_o2/vlvw/de/mcfg_sw.mbn
Edit: Netmon shows its working now… (after a reboot, including hard reset with power+vol up). Doesnt work when i call my mailbox however