[MT3600BE] USB port dead after v4.9.0 — usb_power_mode empty in /proc/gl-hw-info

Router
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Device: GL-MT3600BE (Beryl 7)
Firmware: v4.9.0 (build 2026-07-02, kernel 5.4.281)
Previous working firmware: v4.8.7

PROBLEM:

After upgrading from v4.8.7 to v4.9.0, the USB 3.0 port stopped detecting
any devices. Tested with Huawei USB modem (works on Keenetic router) and USB
flash drive. lsusb shows only root hubs, dmesg has zero USB device events.

ROOT CAUSE:

/proc/gl-hw-info/usb_power_mode is EMPTY (contains only newline).

Factory data in Device Tree has correct value:
/sys/firmware/devicetree/base/gl-hw/factory_data/usb_power_mode = "Factory0x4100"

gl_sdk4_hw_info.ko has the string "usb_power_mode" but does NOT populate
/proc/gl-hw-info/usb_power_mode from DT factory_data on v4.9.0.

USB port requires PD power (usb-power-require = 9V3A). Without usb_power_mode,
the PD/TCPC controller is never initialized, so VBUS is not delivered.
No VBUS → no device detected.

VERIFIED (everything correct):

  • GPIO usb_power (gpio-476): ON (out hi)
  • Port disable flags: 0 (both ports enabled)
  • xHCI and PHY initialize correctly
  • All kmod packages installed, all modules loaded
  • Power-cycled GPIO, unbound/rebound xhci-mtk driver — no effect
  • usb3_disable flag tried in both positions — no effect
  • USB devices work on another router (Keenetic) — hardware is good

STEPS TO REPRODUCE:

  1. Upgrade MT3600BE from v4.8.7 to v4.9.0
  2. Plug any USB device into the USB port
  3. lsusb — only root hubs visible
  4. cat /proc/gl-hw-info/usb_power_mode — empty

EXPECTED BEHAVIOR:

gl_sdk4_hw_info.ko should read usb_power_mode from DT factory_data
and expose it in /proc/gl-hw-info/usb_power_mode, same as v4.8.7.

WORKAROUND:

Downgrade to v4.8.7 restores USB functionality.

1 Like
3

Hi,

Thank you for providing the detailed troubleshooting information.

We tested the same GL-MT3600BE model on firmware v4.8.7 and v4.9.0.
In our local tests, /proc/gl-hw-info/usb_power_mode contained only a newline character on both firmware versions. However, the same USB flash drive could still be detected and mounted normally on both versions, including v4.9.0.
Therefore, we have not been able to reproduce the USB port failure you reported.
Could you please confirm whether you selected Keep Settings when upgrading from v4.8.7 to v4.9.0?
If convenient, could you also reset the router to factory settings while running v4.9.0, without restoring the previous configuration, and then check whether the USB device is still not detected?

Thank you for your cooperation and patience.