RM500Q-AE on R13A01 — QMI/RNDIS/ECM data interface missing from USB descriptor

I have an RM500Q-AE with firmware RM500QAEAAR13A01M4G. The module is completely unusable because the network data interface is missing from the USB descriptor in all USB modes:

  • QMI mode (usbnet=0): Only interfaces 0-3 appear (all serial), interface 4 (QMI data) is missing
  • RNDIS mode (usbnet=3): Only serial interfaces appear, RNDIS data interface is missing
  • ECM mode (usbnet=1): Same issue, no network interface

The serial/AT ports work fine, so I can communicate with the module, but no data connection is possible. This appears to be a firmware bug in R13A01 — I have seen that users on R13A03 have working data interfaces.

Could you please send me:

  1. A working firmware version (R13A03 or newer)
  2. QFlash tool
  3. Windows USB drivers

My E-Mail: heroman1701@gmail.com
I am an individual developer based in Germany.
Thank you for your help.

Dear @Half6217
I have sent the firmware to your email, please check.

For Qflash and Windows driver, please download from website.

Dear Support Team,

I am experiencing a similar issue with my RM500U-CN module.

Module: RM500U-CN
Current Firmware: RM500UCNAAR02A03M2G_01.001.01.001

The module is detected correctly over USB, and all AT command interfaces are working. The modem can successfully register on the cellular network, and I can communicate with it normally through the AT ports.

However, the USB network interface is no longer exposed by the module.

Previously, the module enumerated correctly and provided a usb0 network interface. While testing the PCIe/Ethernet functionality using the AT+QCFG="pcie/mode" and AT+QCFG="ethernet" commands, the USB network interface disappeared. Since then, the module only enumerates with five vendor-specific serial interfaces.

Current USB descriptor:

  • VID = 2C7C:0900
  • bNumInterfaces = 5
  • iConfiguration = pcie
  • Interfaces 0–4: Vendor Specific (serial only)

No RNDIS, ECM, NCM, MBIM, or other USB network interface is present.

I have already tried the following without success:

  • Restored pcie/mode to 0
  • Restored ethernet to 0
  • Tested all supported usbnet modes (1, 3, and 5)
  • Executed the recommended QNETDEVCTL commands
  • Performed AT&F, AT&W, and modem resets
  • Fully power-cycled the module
  • Tested on Ubuntu with different USB configurations

Despite these steps, the USB descriptor remains unchanged and the module never exposes a USB networking interface.

Could you please advise whether this is a known issue?

If available, I would greatly appreciate:

  1. A newer firmware version that resolves this issue.
  2. The corresponding QFlash (or recommended flashing tool) and flashing instructions.
  3. Any recovery procedure or NV reset procedure that restores the original USB networking interface after switching between PCIe/Ethernet and USB modes.

Thank you very much for your assistance.

Kind regards,

Dear @heng
Please try this.
AT+QCFG=“pcie/mode”,1
AT+CFUN=1,1

Thanks @silvia

Upgrading the firmware to R03A05, and then to the latest R03A14, successfully brought back the usb0 interface.