WWAN modem becomes unavailable after suspend

[Marco Moock]

Hello!

I have an HP lt4111. After suspend to ram, it only works every 2/3
times I suspend the system. It works if I suspend and wake it up
again.
It also works immediately after a reboot.

If it doesn't work, it is being detected by lsusb, but not mmcli.

Bus 001 Device 004: ID 03f0:4e1d HP, Inc HP lt4111 LTE/EV-DO/HSPA+ Gobi
4G Module

I also don't see dmesg messages that seem to be relevant to that.

How can I further diagnose that?