Linux option driver not loaded for NMEA port of RM500Q-AE

I’m using a RM500Q-AE within a Linux PC. It is connected by USB.
Modem is working like a charm and I can verify GNSS functionality and fix in a terminal with AT commands. But there are only 3 and not 4 ttyUSB* devices as mentioned in Quectel_UMTS_LTE_5G_Linux_USB_Driver_User_Guide_V3.0.pdf . Option driver is not loaded for If#=1.

For me it look like the AT and DBG Terminals are there but the GNSS port is missing. How can I enable it ?

Thx for any help!

AT+QCFG: “USBCFG”,0x2C7C,0x800,1,1,1,1,1,0,0
$ uname -a
Linux stl-5g-1 6.2.0-39-generic #40~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Nov 16 10:53:04 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
T:  Bus=02 Lev=01 Prnt=01 Port=02 Cnt=02 Dev#=  3 Spd=5000 MxCh= 0
D:  Ver= 3.20 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs=  1
P:  Vendor=2c7c ProdID=0800 Rev= 4.14
S:  Manufacturer=Quectel
S:  Product=RM500Q-AE
S:  SerialNumber=eda06996
C:* #Ifs= 5 Cfg#= 1 Atr=a0 MxPwr=896mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=30 Driver=option
E:  Ad=81(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 1 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=40 Driver=(none)
E:  Ad=83(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=82(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=85(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=84(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=87(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=86(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I:* If#= 4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=qmi_wwan
E:  Ad=88(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
E:  Ad=8e(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E:  Ad=0f(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms

Hi Martin,

please see [PATCH] USB: serial: option: add Quectel RM500Q R13 firmware support - Reinhard Speyerer.

Regards,
Reinhard

1 Like

Thank you very much for the quick reply!

Is it possible to downgrade the modems to a firmware prior R13, i.e. R12 to solve the problem for the moment? Where can I find such firmware and which tools are required for flashing?