SBC is now recognized as the Sweet Potato- nice. However, USB doesn't work at all; no USB device work once Kodi starts.
The only issue I see in the log is something to do with spi-nor flash, but I've no idea what that could be. The description above sounds a bit like an inadequate PSU problem. There's no software interaction between Kodi and USB, but starting Kodi will require the GPU and HDMI bits to do something, which increases power draw, which might result in bad behaviour if the PSU is weak. What's the spec of the PSU?