Modem Firmware¶

The MF286D uses an mPCIe Cat 12 LTE module (MDM9250 based) connected over QMI. OpenWrt talks to it through /dev/cdc-wdm0.

Check the current modem version¶

Connect to the modem AT port (usually /dev/ttyUSB1) with picocom, minicom or gcom and send ATI:

Manufacturer: ZTE CORPORATION
Model: MF286DMODULE
Revision: BD_TELIAMF286DV1.0.0B11
SVN: 11
IMEI: 86XXXXXX
+GCAP: +CGSM,+DS

The revision suffix (...B11 here) is the modem build. The community reports that B12 is the stable build for OpenWrt; older builds can drop the data connection.

Updating the modem to B12 (community procedure)¶

The update runs from OpenWrt, over ADB to the modem's /cache plus AT commands. Updates are sequential: B03 → B06 → B11 → B12, one step at a time.

1. Install adb on the router (apk add android-tools or an equivalent package).
2. Extract the matching imageBxxnaByy folder from the community "Nordic Modem Update (up to B12)" package. It contains delta.package and delta.signature.
3. Push both files to the modem:

adb push delta.package /cache/
adb push delta.signature /cache/

1. On the AT port (/dev/ttyUSB1), step through the update:

at+fotactr=0     # 0,0  -> modem sees the package
at+fotactr=1     # 1,0  -> validation ok (1 = failed, 2 = waiting)
at+fotactr=5     # 5,<bytes> -> size of the update package
at+fotactr=8     # 8,0  -> clears old *.flg files in /cache
at+fotactr=2     # starts the update

1. Wait about five minutes; the modem reboots and comes back.
2. Repeat for the next step until B12, then reboot once more and re-check ATI.

Source: makebit/mf286d-openwrt and the original thread on eko.one.pl.

What this firmware does not do¶

NoobWRT does not flash modem firmware. The modem keeps whatever build the device shipped with. There is no tested, reversible modem upgrade path maintained in this repository.

Checking the modem¶

# QMI mode / device presence
ls -l /dev/cdc-wdm0
uqmi -d /dev/cdc-wdm0 --get-version

# ModemManager view
mmcli -L
mmcli -m 0

# Signal and operator (3ginfo uses the same AT port)
sms_tool -d /dev/ttyUSB1 status

The reference image points the 3ginfo and modemband apps at /dev/ttyUSB1. If your modem enumerates on a different AT port, change:

uci set 3ginfo.@3ginfo[0].device='/dev/ttyUSB2'
uci set modemband.@modemband[0].set_port='/dev/ttyUSB2'
uci commit

Switching the WAN protocol¶

The shipped config uses QMI. ModemManager and MBIM are also available:

# ModemManager
uci set network.wan.proto='modemmanager'
uci set network.wan.device='/dev/cdc-wdm0'
uci commit network
/etc/init.d/network restart

The APN page (/apn.html) can switch between QMI, MBIM and ModemManager and write the APN for you.