EG25 shows only DM Port

IoT Modules LTE-A Module
1

Hello, oneday my quectel module shows only DM port or RNDIS mode.

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image1352×498 59.1 KB

Even my module’s “usbnet” is set on 0, reflashed firmware, used AT+QPRTPARA=3.
Module seems not broken, because everything without usb conns are working. (ims, ata, ath, RING from UART)
can i get some help with this?

EG25
Revision: EG25GGBR07A08M2G
EG25GGBR07A08M2G_A0.301.A0.301

2

Hi,

Based on the behavior you described (only DM port visible) and similar cases we’ve seen, this is usually related to USB configuration or the module entering a restricted mode.

Since your UART interface is still accessible, you can try the following checks:

1. Verify USB configuration

Please query the current configuration:

AT+QCFG="usbcfg"

For Quectel EG25-G, a typical default would look like:

+QCFG: "usbcfg",0x2C7C,0x0125,1,1,1,1,1,0,0

Pay attention to:

  • 5th parameter → AT port
  • 6th parameter → Modem port

If either is 0, those ports will not enumerate over USB.

You can try restoring full port visibility:

AT+QCFG="usbcfg",0x2C7C,0x0125,1,1,1,1,1,0,0

Then reboot the module.

2. Check USB_BOOT pin state (Pin 115)

If the module is detected only as a DM port (e.g. Qualcomm QDLoader), it may be entering forced download mode.

  • Ensure USB_BOOT (Pin 115) is not pulled high (1.8V) during power-up
  • If this pin is high at boot, the module will only expose the DM interface

3. Check USB loading behavior

AT+QCFG="usbee"

If it returns 1, USB enumeration may be delayed until modem initialization.

You can try:

AT+QCFG="usbee",0

4. Verify USB connection state

AT+QCFG="usbmode"

Expected responses:

  • DISCONNECTED → No VBUS detected
  • SUSPEND → Host connected but idle
  • CONFIGURED → Normal working state

Recommended sequence

  1. Restore USB config
  2. Set usbee to 0
  3. Reboot module
  4. Confirm hardware (especially USB_BOOT pin)