Hello,
I've been tinkering with T99W175 from AliExpress. It's probably the cheapest option right now for 5G connectivity and I'm happy to report that I got it working.
I will just give some bullet points if someone wants to follow my config:
AT+CUSTOMER should be set to 0 or 8 (tested both, working)
AT+USBSWITCH should be 90D5
Modem has to have jumper soldered on the back side and also pin 2 isolated from the M.2 to USB converter.
Then we can go over some software. Starting from clean install you need following packages (go to LuCi, system, software) : mbim-utils, kmod-usb-net-cdc-mbim, libmbim, umbim, modemmanager
After installing those packages you can go to Network-Interfaces-Add new. As a protocol you should chose ModemManager, as a device your cdc-wdm0 (not ttyUSB, you should not get ttyUSB at this point), APN, authenticaton and IP type according to your cellular provider. Also don't forget to set firewall zones for this interface, i set mine to WAN.
After this save, save&apply and you should be good to go.
To diagnose what's happening you can use GL.iNET GUI (system - log). Unfortunately there's no OEM GUI support for this kind of connection, I will try to get support involved into adding support for original GUI as it's easier to manage this connection than using mmcli in shell.
If you need ttyUSB exposed you need to go into ssh, then type
cat /sys/kernel/debug/usb/devices
You should see some of your devices with "Driver=none". To assign a driver you just need to go and type
echo "05c6 90d5" > /sys/bus/usb-serial/drivers/option1/new_id
Default baudrate is 9600, for AT commands I use YAT terminal on Windows, port settings are 9600 8N1N
After all of this my mmcli looks like this:
And speedtest with a 4G connection (didn't yet set proper allowed and preferred mode in mmcli)
Now all that is missing is proper GL GUI support. At this moment the cellular connection seems to get higher priority than WLAN Repeater (should be other way around for me) and there's not a clear way to change it. Also there's no clear way to manage your modem (for example i need to use Windows to change AT commands).
All in all, for sub 40$ 5G modem this thing rocks.
