Has anybody experience in booting from a USB device?
No, I am going to try it soon. I think it is not that hard to do. Does your board support booting from USB devices? My guess would be to take a standard buildfile (the one without diskboot) and replace the devb-eide stuff with devb-umass. I think you also need a kind of timout after starting the driver to make sure the partition is available to you to load the rest.
If I am not mistaking, someone else around here asked that question too. I can’t recall the answer though.
And you need a BIOS that support booting from USB device.