Last few weeks I satvery far away from all my computers. The reason, you ask? We have changed our flat against a bigger one, so that all of us have more room for work, amusement and a living. Moving affects thousands of resources, costs money and affects health. I bet I have more gray hair now than a month ago ;)
I have applied for the mass storage bouty recently and I have been working on it again during last few days. This USB class adds an exec-style device to the system, named usbmss.device. It allows programs and filesystems not aware of AROS' USB stack to talk with the MSS class devices attached to the computer. Currently, it's able to forward many exec-style commands to and from the USB device. It does not report medium change and lies about media type (it says that evertything is of type DG_DIRECT_ACCESS). Once this issues will be addressed, the device interface will be completed. Then, the USB Mass Storage will call expansion's AddBootNode function and I will hopefully boot AROS from USB stick.
Then, the bounty might be considered complete. ;)
PS. On the screenshot below, the freshly created FAT32 partition on virtual MSS device on QEmu.