The attached patch fixes ethernet tethering to work with a PinePhone. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=64e049102d3de3e61409cb6019403a9e689dfda6 mentions that the typical RNDIS is a variant of CDC ACM with CSP 0xff0202, so I added that and also noted that the existing value works with Nexus 5 (as mentioned in the original commit). I also updated the man page for nusb to fix a typo and to enumerate the current list of supported types, and updated sys/src/9/boot/nusbrc to automatically detect when an RNDIS device is connected.