In contrib/miller on 9p.io there are new kernel binaries 9pi4 and 9pi4cpu, now with USB3 fully supported (thanks cinap). If you build from the source in contrib/miller/9/bcm, you'll need an updated usb/usbd command to initialise the more complicated root hub topology of the pi4; for convenience the updated source files are in cmd-usb.tar in that directory. Eventually I'll supply a corresponding patch for the 9legacy collection.
I still need to implement kmap, to gain access to the upper 2GiB of a 4GiB pi4. For the next couple of weeks I have other distractions, but I'll get there ...
