Fumbling With OpenWrt and RM500U-CN

Apologies, basically looking for some help , I am far from an expert when it comes to Linux or OpenWRT , though I appreciate it, and my experience with it is just basic, replacing crappy stock routers with OpenWRT to use the extra functions , such as VLANS , multiple DHCP , FIrewall rules and power schedules ..

My next challenge was finding affordable internet 50Mb up , so 5G with an unlocked or Open Source router was an idea that had drove me to into a 5G rabbit hole until I came across Wavshare's 5G solution here , which includes a Quectel RM500U-CN M.2 modem, which has Band 78 support (used locally by Cells here in UK) , despite being manufactured for the Chinese Market .. These are allegedly sold worldwide , so I had the impression that I could get the same modem working in one of my X86 PC's or Routers with M.2 slots, running OpenWRT


I purchased one of these Quectel RM500U-CN M.2 Modems (Just the modem , not the entire Hat) for $50 along with a batch of computer parts from Taobao .. I had a ZBT 1602 with M.2 adapter ,an M.2 USB caddy for 4G/5G Networks cards and also a ITX board with an M.2 1 x M.2 Socket for network PCIE/USB mode

However I am lost , when it comes to getting this working . I experiemented with the USB first , to can get Windows to recognize the modem , update the firmware , and also send AT commands through a terminal but . Though I am just stabbing in the dark , so to speak . It just shows as a disconnected as an ethernet device , after exhausting the suggested commands .

I have read many articles and guides .. So there is some encouragement , apparently the modem is MBIM Compliant here on Openmptcp github , so I guess that suggests it can work

The modem woks with OpenWRT According to Wavshare's OpenWRT tutorial here,

Though this suggests to put the modem into QMI mode .. Though the Former link suggests to use MBIM mode - maybe I am just thick ?

I currently have the Modem attached via USB caddy to a OpenWRT ITX X86/64 Build . I was hoping it would it would be recognised , I am guessing this is just wishful thinking

If anyone can advise , this would be great ..

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The easiest way is probably use ECM, AT+QCFG="usbnet",1
OpenWrt configuration per https://openwrt.org/docs/guide-user/network/wan/wwan/ethernetoverusb_cdc
You will need to send some extra commands to the modem to initiate the connection, similar to Quectel EC200T-CN LTE module not working in OpenWrt - #18 by AndrewZ

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Would you or anyone else be interested in a team view or other remote connection ? I could offer a donation and for posterity document the the solution