Which modems does Auto Pi support?

Hi everyone,

As a next step to the setup described herein:
https://community.autopi.io/t/hardware-support-for-option-driver-recognized-modems/2242
I flushed AutoPi Core into the SD, connected the AutoPi Telematics Unit - DIY Edition to RPi3 B+,
and played with some modems.

I was able to bring up the unit and connect to it over web via the generated wifi hotspot.
I then tried to connect a number of modems to AutoPi directly (Telit LE910-EU v2, LE910C4-EU, Simcom SIM7100E, Quectel EC25-E), but none worked.

I kept getting the following error with each modem:

Command failed
Command: cmd.run_all qmi-manager up
Exit code: 1
[WARN] Command failed with exit code 1: test -c /dev/cdc-wdm0
[WARN] Command failed with exit code 1: test -c /dev/cdc-wdm0
[WARN] Command failed with exit code 1: test -c /dev/cdc-wdm0
[WARN] Command failed with exit code 1: test -c /dev/cdc-wdm0
[WARN] Command failed with exit code 1: test -c /dev/cdc-wdm0
[WARN] Command failed with exit code 1: test -c /dev/cdc-wdm0
[ERROR] QMI device not found ‘/dev/cdc-wdm0’

So I figured out that AutoPi requires a modem exposing Qualcomm’s proprietary qmi interface via the qmi_wwan driver.

Thus I attempted the same setup with the Telit LM940 modem, which exposes this interface. To my surprise it failed again with the same error, and although the modem appeared in lsusb, no /dev/cdc_wwan* nor /dev/ttyACM* nor /dev/ttyUSB* mappings were created.

As a final step, instead of using AutoPi’s mPCIE adapter, I’ve connected directly to Pi’s USB, an mPCIE <-> USB adapter, and plugged into it the modem. This time all worked fine! Both /dev/cdc_wwan* entry was created, as well as /dev/ttyUSB* entries, and I was able to configure APN via the locally exposed webpage through the wifi’s hotspot, and connect to the internet via the modem!

I’m wondering if I missing anything in my setup? Is this the expected behavior?
And would like thus to understand which modems should AutoPi officially support, when connected directly to the unit?

I would also like to hear from anyone who attempted this simple setup - which modems worked for you?

Many Thanks!
Vitaliy