The Unsupported Wifi Dongle Thread

Technical Support for Routers
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Hi everyone,

I would like to start a thread where we can collect lessons learned while attempting to use unsupported wifi dongles.

The most common use case is that someone wants to add a directional wifi dongle for WWAN access, and use the built-in radios in the GL.iNet router for WLAN access.

As you may know, GL.iNet does support a couple specific USB wifi chipsets on the Brume devices, but otherwise this type of setup is completely unsupported. However, it may be possible to make it work for some scenarios, most likely requiring configuration via Luci and/or the command line.

This thread is for collecting info & tips on how to do so, with the understanding that GL.iNet does not support it.

I’m going to reserve a couple posts at the top of the thread which I can edit to concisely list what’s discovered.

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Functional wifi dongles

This post will be used to maintain a list of dongles which function properly, and without limitations on stock GL.iNet firmware if they are set up via Luci and/or the command line.

I will keep it updated as time goes on.

Tested and known working

  • (none)

Currently, the list has zero entries because I have never gotten a wifi dongle fully operational this way. This may change very soon.

Suspected good

  • rt2800 / rt3070 based?

Known problematic

  • mt76 based devices may or may not have severe problems with txpower - fix has not yet landed in vanilla OpenWRT or stock GLi firmware
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Key points

I will keep this post updated with key lessons learned when trying to use these dongles.

Plug-in order matters

The stock firmware is written to expect the number & type of radios which shipped with the router, and not the dongle you are attempting to add. This can lead to problems:

  • Plugging the dongle in before boot can cause failure to boot or failure to enable any radios at all.
  • Plugging the dongle in after the router has booted may not bring it up the way you expect, for example you may need to “restart” the interface in Luci before it will work.

USB power matters

  • Especially if you are using a high-power or long range dongle, the power demand may exceed what the router can supply over its USB port.
  • You should always ensure a good power supply, but some dongles may demand more than the port can supply even with the GL.i-provided power brick.
  • Some dongles may demand high power for brief periods even when their txpower is set low.
  • USB 2.0 power meters may refuse to pass enough current; try to get a USB 3 meter.
  • Always test with and without your power meter, some meters cause problems themselves.
  • If you are seeing USB disconnect errors in the logs, insufficient power is likely the problem.

GL.i UI and Luci/CLI are not necessarily kept in sync

  • Once you add an unsupported radio, changing certain settings and/or using certain features in the GL.i firmware may behave in unexpected ways.
  • It may be better to do all your changes in Luci and/or the CLI and touch the GL.i interface as little as possible once you have added an unsupported radio.

Vanilla OpenWRT may not be the answer

  • The quality of unmodified OpenWRT on GL.i devices can vary. Some devices are supported better than others.
  • The most recent version of OpenWRT may not be available on all devices, as some use proprietary kernels, etc.
  • Specific fixes/improvements GL.i has made for the hardware in their routers may not have made it back to upstream OpenWRT yet.

Vanilla OpenWRT is not really intended for devices which change configuration often

  • The GL.i firmware goes a very long way to make their devices useful as “travel routers” - routers which experience frequent configuration changes. The OpenWRT core is far less suitable for this type of use case.
  • Prepare to learn a lot about OpenWRT and figure out how to automate your configuration changes if you want to use a vanilla OpenWRT device as a travel router.
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For the first time ever, I have managed to connect to WWAN uplink via an unsupported (rt3070) dongle, running stock GL.iNet firmware, and the VPN is working.

It’s fragile as the stock firmware doesn’t necessarily know what to do with 3 radios instead of the 2 it expects, but still… IT’S ALIVE

I’ve been working toward this for probably close to 3 years, delayed by all sorts of personal tribulations, and by the MT76 txpower bug. But this sign of life is very encouraging, and I hope to be updating this thread further soon.

Edit: The unit I had initial success with is this one, an indoor-outdoor directional 2.4GHz-only unit with claimed 10dB gain from Rokland Tech, Florida, USA. Despite what the URL says, this is a generic device, not an Alfa unit.

I do not have this dongle “fully working” yet, but I can confirm that it is functional up to a txpower of 400mW on the Slate Plus (GL-A1300). Higher power demands too much from the USB port and leads to disconnects.

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