RM500U-CNV /dev/ttyUSB2 not responding

IoT Modules 5G Module
1

I believe I put my modem into MBIM mode and have found that my modem no longer responds to commands on /dev/ttyUSB2. The only serial port that responds to commands is /dev/ttyUSB3 and have re-flashed with the latest firmware but have been unable to get USB2 to respond again. I’ve been trying to get the device to work in a BPI R4 Pro which should have drivers enabled for the modem.

Here is my /sys/kernel/debug/usb/devices before and after enabling the serial through “sh -c ‘echo “2c7c 0900” > /sys/bus/usb-serial/drivers/generic/new_id’”

T:  Bus=04 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#=  3 Spd=5000 MxCh= 0
D:  Ver= 3.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs=  1
P:  Vendor=2c7c ProdID=0900 Rev= 4.04
S:  Manufacturer=Quectel
S:  Product=RM500U-CNV
S:  SerialNumber=0123456789ABCDEF
C:* #Ifs= 7 Cfg#= 1 Atr=c0 MxPwr=504mA
A:  FirstIf#= 0 IfCount= 2 Cls=e0(wlcon) Sub=01 Prot=03
I:* If#= 0 Alt= 0 #EPs= 1 Cls=e0(wlcon) Sub=01 Prot=03 Driver=(none)
E:  Ad=82(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=(none)
E:  Ad=81(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
E:  Ad=83(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
E:  Ad=84(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 4 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
E:  Ad=85(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
E:  Ad=86(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=05(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 6 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
E:  Ad=87(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=06(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms

T:  Bus=04 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#=  3 Spd=5000 MxCh= 0
D:  Ver= 3.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs=  1
P:  Vendor=2c7c ProdID=0900 Rev= 4.04
S:  Manufacturer=Quectel
S:  Product=RM500U-CNV
S:  SerialNumber=0123456789ABCDEF
C:* #Ifs= 7 Cfg#= 1 Atr=c0 MxPwr=504mA
A:  FirstIf#= 0 IfCount= 2 Cls=e0(wlcon) Sub=01 Prot=03
I:* If#= 0 Alt= 0 #EPs= 1 Cls=e0(wlcon) Sub=01 Prot=03 Driver=(none)
E:  Ad=82(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=usbserial_generic
E:  Ad=81(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=usbserial_generic
E:  Ad=83(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=usbserial_generic
E:  Ad=84(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 4 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=usbserial_generic
E:  Ad=85(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=usbserial_generic
E:  Ad=86(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=05(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 6 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=usbserial_generic
E:  Ad=87(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=06(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
2

Use option driver instead. If your kernel is not outdated, the required vid:pid should be already there.

3

Thanks jfrog, pointing me that way helped me notice that the option.ko driver was failing to launch on start up. Re-flashing OpenWRT has got the driver working correctly, I just didn’t get usb0 to show from my limited testing yesterday with the SIM, though that could be due to wrong AT commands as I am inexperienced. Do you know if there is a full manual of the RM500U-CNV capabilities and AT commands?

4

Please consider asking further questions in their forum.

5

Dear @wednesday
Actually,RM500U didn’t support MBIM mode.
I will sent AT command document to you via Message, please check.