MC7455: EMM attach failed

IoT Modules MC/EM Series
8

Ok, I installed GobiNet and GobiSerial from https://source.sierrawireless.com/resources/airprime/software/usb-drivers-linux-qmi-software-s2,-d-,36n2,-d-,55/

And i set at!usbcomp=1,1,10D.

I also installed ModemManager and setup the device whitelist in /lib/udev/rules.d/78-mm-whitelist-internal-modem.rules as follows:

ACTION!="add|change|move", GOTO="mm_whitelist_internal_modem_end"
    ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9071", ENV{ID_MM_DEVICE_PROCESS}="1"
    LABEL="mm_whitelist_internal_modem_end"

However, ModemManager isn’t recognizing the modem firmware:

Feb 19 19:16:01 phone ModemManager[14170]: <warn>  Couldn't get detailed info for PRI image with build ID '02.30.01.01_ATT': QMI protocol error (71): 'InvalidQmiCommand'
Feb 19 19:16:02 phone ModemManager[14170]: <warn>  Couldn't get detailed info for PRI image with build ID '02.30.01.01_GENERIC': QMI protocol error (71): 'InvalidQmiCommand'
Feb 19 19:16:02 phone ModemManager[14170]: <warn>  Couldn't get detailed info for PRI image with build ID '02.30.01.01_SPRINT': QMI protocol error (71): 'InvalidQmiCommand'
Feb 19 19:16:02 phone ModemManager[14170]: <warn>  No valid firmware images listed. Assuming firmware unsupported.
Feb 19 19:16:02 phone ModemManager[14170]: <info>  Modem: state changed (unknown -> disabled)

So I manually enabled the modem with mmcli -m 0 -e:

Feb 19 19:16:04 phone ModemManager[14170]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (disabled -> enabling)
Feb 19 19:16:04 phone ModemManager[14170]: <warn>  (ttyUSB2): port attributes not fully set
Feb 19 19:16:04 phone ModemManager[14170]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: 3GPP Registration state changed (unknown -> registering)
Feb 19 19:16:04 phone ModemManager[14170]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: 3GPP Registration state changed (registering -> home)
Feb 19 19:16:05 phone ModemManager[14170]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: state changed (enabling -> registered)
successfully enabled the modem

But ifconfig is still not showing the interface, even after restarting NetworkManager.

How do I get the wwan interface to show in ifconfig?