Modem control

luci-app-hh71vm-modem and the hh71vm-modemd daemon behind it are part of the base firmware. Nothing has to be installed and nothing has to be enabled.

What it does

The HH71VM is two separate Linux systems in one case: the Realtek half runs OpenWrt, and the Qualcomm half runs the modem with its own firmware. They are joined over USB/RNDIS. Every modem operation therefore has to cross that link, and hh71vm-modemd is the only thing on this side that does.

The daemon keeps a parsed snapshot of the modem in memory and in a JSON file and refreshes it in the background, so the web pages open immediately instead of waiting on the radio. LuCI never talks to the modem directly: the pages call ubus, rpcd hands the call to the daemon, and the daemon serialises it against everything else on the single control channel.

The pages

Open Modem in the LuCI menu.

System > About this port carries the licence information and the source link.

Some operations are slower than a single web request is allowed to be. USSD is the clearest case: AT+CUSD returns OK immediately and the network's answer arrives later as an unsolicited message. Those run as a job the page polls, and the page shows how long the network has been processing the request rather than failing at the request ceiling.

Command line

The daemon is also usable directly, which is the fastest way to check something without the browser:

hh71vm-modemd --at 'AT+CSQ' 'AT+COPS?'
hh71vm-modemd --call sms_list

--foreground -v runs it in the terminal with verbose logging instead of as a service. The service itself is the usual /etc/init.d/hh71vm-modemd.

The same API is reachable over ubus, which is what a script on the router should use:

ubus call hh71vm-modem status
ubus call hh71vm-modem sms_list

Restart the modem

Overview → Control → Restart modem. Some settings changes on the Qualcomm side (an APN edit is the one reported so far) leave the modem's data session unreliable until the radio is power-cycled. This button parks the radio and brings it back — AT+CFUN=0, a pause the radio genuinely needs, then AT+CFUN=1 and a full session re-setup — the same recovery hh71vm-modemd already runs on its own when it finds an empty SIM slot after boot. Mobile data, calls and SMS are unavailable for about 10 seconds while the radio reconnects; the confirmation dialog says so.

Verified live 2026-09-16. The router's own uptime ran straight through the bounce with no gap, the AT control channel never dropped, the session re-setup and the scheduled message-store resync both ran afterwards, and the modem came back to cfun 1 with the data path up.

An earlier version of this button sent AT+CFUN=1,1, a full Qualcomm baseband reset, as an attempt to get closer to an actual power cycle. Confirmed live 2026-09-15: this takes the whole board down, not just the modem. The Qualcomm half provides the USB gadget that carries both the AT control channel used here and eth2 (the Realtek side's link to the modem); resetting the baseband tears that gadget down mid-flight, and the Realtek kernel does not survive the eth2 disconnect — the board comes back roughly 90 seconds later having done a full boot, hh71vm-modemd included. So there is still no confirmed way to reset just the Qualcomm baseband on this hardware short of an actual power cycle (disconnect power, wait, reconnect) — if the radio bounce above does not help, that is the next step, same as before.

Notes

• The daemon owns the modem channel. Do not open a second AT, telnet or QMI session to the Qualcomm half while it is running; the two will interleave and both will read nonsense.
• A router that boots with no SIM in the slot re-reads the slot by itself, so inserting a SIM afterwards does not require a reboot.
• Incoming messages are announced by the modem rather than polled for, which is what keeps the unread flag meaningful.