Testing Sierra Wireless EM7345 4G LTE on TOFU with Raspberry Pi CM4

[munerangus]

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I managed to prepare my Oratek TOFU board with a CM4 (after testing ubuntu server, OpenWRT, and a couple more, I settled with Raspberry Pi OS since I cannot use Oratek's recommended BALENA for other reasons). I'm flashing the CM4 to boot from its 16GB eMMC.

Raspberry Pi OS enables M.2 and USB power out of the box and recognizes the CM4's WiFi as well as the EM7345 4G LTE Sierra Wireless adapter. I think I am in a better starting point (OpenWRT for CM4 did not recognize Wireless adapters at all in my setup).

After installing minicom, I'm having a hard time getting the modem to accept AT commands for basic configuration... Did not have this issue with non-arm hardware/distributions and the same Sierra Wireless adapter. Has anybody been successful testing a similar combination?

For additional information:

Detected modem (ttyACM0)

pi@tofucm4:~ $ ls /dev/tty*
/dev/tty    /dev/tty14  /dev/tty20  /dev/tty27  /dev/tty33  /dev/tty4   /dev/tty46  /dev/tty52  /dev/tty59  /dev/tty8
/dev/tty0   /dev/tty15  /dev/tty21  /dev/tty28  /dev/tty34  /dev/tty40  /dev/tty47  /dev/tty53  /dev/tty6   /dev/tty9
/dev/tty1   /dev/tty16  /dev/tty22  /dev/tty29  /dev/tty35  /dev/tty41  /dev/tty48  /dev/tty54  /dev/tty60  /dev/ttyACM0
/dev/tty10  /dev/tty17  /dev/tty23  /dev/tty3   /dev/tty36  /dev/tty42  /dev/tty49  /dev/tty55  /dev/tty61  /dev/ttyAMA0
/dev/tty11  /dev/tty18  /dev/tty24  /dev/tty30  /dev/tty37  /dev/tty43  /dev/tty5   /dev/tty56  /dev/tty62  /dev/ttyprintk
/dev/tty12  /dev/tty19  /dev/tty25  /dev/tty31  /dev/tty38  /dev/tty44  /dev/tty50  /dev/tty57  /dev/tty63  /dev/ttyS0
/dev/tty13  /dev/tty2   /dev/tty26  /dev/tty32  /dev/tty39  /dev/tty45  /dev/tty51  /dev/tty58  /dev/tty7

Details of the adapter:

pi@tofucm4:~ $ sudo mmcli -m 0
  --------------------------------
  General  |            dbus path: /org/freedesktop/ModemManager1/Modem/0
           |            device id: 896774c98c060b74ca4794ab2ade283a2165f8d9
  --------------------------------
  Hardware |         manufacturer: Sierra Wireless Inc.
           |                model: Sierra Wireless EM7345 4G LTE
           |    firmware revision: FIH7160_V1.2_WW_01.1415.07
           |         h/w revision: XMM7160_V1.2_MBIM_GNSS_NAND_RE
           |            supported: gsm-umts, lte
           |              current: gsm-umts, lte
           |         equipment id: 013937006701559
  --------------------------------
  System   |               device: /sys/devices/platform/scb/fe9c0000.xhci/usb1/1-1/1-1.1
           |              drivers: cdc_acm, cdc_mbim
           |               plugin: sierra
           |         primary port: cdc-wdm0
           |                ports: cdc-wdm0 (mbim), ttyACM0 (at), wwan0 (net)
  --------------------------------
  Status   |       unlock retries: sim-pin2 (10)
           |                state: disabled
           |          power state: on
           |       signal quality: 0% (cached)
  --------------------------------
  Modes    |            supported: allowed: 2g, 3g, 4g; preferred: none
           |              current: allowed: 2g, 3g, 4g; preferred: none
  --------------------------------
  IP       |            supported: ipv4, ipv6, ipv4v6
  --------------------------------
  3GPP     |                 imei: ****** (removed just in case)
           |        enabled locks: fixed-dialing
  --------------------------------
  3GPP EPS | ue mode of operation: csps-2
  --------------------------------
  SIM      |            dbus path: /org/freedesktop/ModemManager1/SIM/0

[geerlingguy]

Just wanted to link also to https://github.com/geerlingguy/raspberry-pi-pcie-devices/issues/344 — that Quectel device supposedly works with Pi 4 model Bs according to many, but I haven't heard of any first-hand accounts of it (or this EM7345) working with the CM4... though they should.