Librem 15 issue with USB-C data-only port


I’d like to use the USB-C (data only) port of my Librem 15 for an Ethernet cable connection. To convert RJ45 to USB-C I am using an i-tec Thunderbolt 3 Dock. The dock works perfectly with both my MacBook Pro and my Dell Precision 7510. With my Librem 15, it does not work.

This does not seem to be a driver issue, because when I connect my iPhone with a USB-C cable to my Librem 15, it detects a cable connection and the Librem 15 uses the Internet connection of my iPhone.

I am aware that the Librem 15 does not support Thunderbolt 3, but only USB. But is this the reason? If so, there should be adapters that convert Thunderbolt 3 to USB (with the same USB-C connector). I did not find such adapters.

i-tec does not answer my support question - maybe I have more luck here. I’d like to know

  1. if I can make my Thunderbolt 3 dock work with my Librem 15, potentially by buying an additional adapter between the two devices, or
  2. if this is not possible, what do i have to buy to convert RJ45 to USB-C so my Librem 15 will recognize a connection just as it does when being connected to my iPhone. This second solution is sub-optimal, because each time I switch my working laptop I would have to disconnect the RJ45 cable from the dock and plug it into the special adapter required for the Librem 15.

Thank you!

Best regards

I would guess that the problem is that this dock wants to use USB-C in “alternate mode”, specifically Thunderbolt alternate mode and that is not supported on the Librem 15 - for the same reason that you can’t use the USB-C port in DisplayPort alternate mode.

In that case it could be confusing to describe the USB-C port as “data only”. It might be more accurate to describe it as “USB only”.

If all you want is ethernet, you may be better off using an ethernet USB dongle and using a normal USB 3.0 port (type A, not type C) e.g. Terrible WiFi performance with Librem13, Librem15


Thank you very much for your expert answer, that‘s exactly what I wanted to know :slight_smile:

Just as a side note: In fact I usually contacted Purism support via email when I had questions about my Librem 15. Most of then were answered very professional. Although the Librem 15 has some flaws I find the concept convincing and I am hoping there will be a v5 :slight_smile: