I have been using this for a few weeks now.
Firstly it should be on the repos and maybe in CSSU since it is a more natural way to find and control the USB mode.

Like h-e-n it usualy takes 2-3 tries to get my Sandisk 16GB thumb drive or other drive mounted. Maybe reclicking on the USB master mode could make for an easier retry on mounting a drive if the first attempt failed rather than having to jump back to slave before trying master again.