I use the USB gadget mode (OE kernel 2.8.28rcX) and everything works.

No I am looking for a solution that I dont have to shutdown the BB
each time. One idea is to mount the root filesystem read-only. The
question is which directoriesdo I have to put on a read-write
partition when I use Angstrom?

Or are there better solutions or ideas for this problem?

Thankfull for any input - Robert