I'm trying to disable USB3 entirely on my raspberry pi 4 running Ubuntu server but I can't find a way to do it. Some things that I've tried are:
- Blacklisting xhci - doesn't work because it's a builtin module.
- Using setpci as documented here to disable it - this command doesn't work because
-H1isn't an argument in the version of
setpcithat is available. Without
-H1it doesn't seem to do anything.
- Disabling USB 3 at some lower level - normally you can do this in the bios but I think the pi doesn't have a bios, I couldn't find any other way to do this.
Is there anything else I can try?
More context: I'm hoping that this will allow me to use more than 32 USB devices as explained here.