Can't access device rm520n-gl module on openwrt/lede

IoT Modules 5G Module
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1

Hi openwrt my router can’t access the module. can’t access device /dev/ttyUSB2. the action i take to reflash/reinstall the openwrt firmware. But still have same error can’t access device.

The original protocol is QMI but i switch to MBIM and unable to revert to QMI and my 5G module keep disconnect and connect in system.

log
found RM520N-GL have no

switch data file.
can’t access device.

is there any solution to fix this 5G module? it keeps connect and disconnect on modem router

2

I believe I’ve had this same issue, the fix is to use ttyusb3 to connect to run AT commands - you can also map the ports for different functions, I know I had to set ttyusb2 and ttyusb3 - I was running the Goldenorb/Rooter fork - there is a large post you can search on whirlpool . net . au

3

It happened to me too. Don’t use mbim, it’ll disconnect and not get recognized. Use putty then return it to qmi mode.

4

Any direct reference to ttyUSBx is potentially wrong.
This modem has its AT command port on USB If#= 2 and you need to check which tty device this interface is mapped to.

5

I am also using openwrt on wg1608 with rm520. Try tty on USB3. Return it back to qmi mode. If that doesn’t work better use usb adapter plug it to pc and use quectel software to return it to qmi.

Mbim doesn’t improve speed at all plus it isn’t stable. It is by using software and hardware offloading that you’ll notice speed improvement with openwrt.

1 Like
6

My router is mapped on USBtty2

7

Do i need usb adapter to change via putty? Thank you.

8

which tutorial do i need to follow to use quectel software? and which software? Thank you

9

I can email you quectel usb debug tools tomorrow and windows driver. The link quectel gave me doesn’t work anymore. Leave email add.

10

You don’t need an adapter or putty.
Install (if not installed already) picocom or any other terminal app in OpenWrt and access your modem as
picocom /dev/ttyUSB2
Then type the AT commands you need.

11

I was able yo revert mine by installing socat in openwrt then send ATcommands in putty. My rm520 would use ttyUSB3

Using putty,

socat - /dev/ttyUSB2,crnl
Or socat - /dev/ttyUSB3,crnl

AT+QCFG=“usbnet”,0

1 Like
12

Hi Thank you Roddel Fernando,
My email address is Rahmatandroid65 @ Gmail com

13

I have revert back to stock Firmware (Mesh) no support on installing picocom /terminal…
does it support to change via Telnet?

14

Thank you for the information,

i have solve this issue via chmod
and change it back modem protocol in openwrt.