Originally Posted by ju1da
If your host OS win 8.1, fastboot mode will not work. Your phone cannot detect by the host, so you cannot also connect it to Guest OS. SO, VM is not the solution by now.
I hate to admit this, but he's right. I've got win8.1 (upgraded from win8) and in neither OS could fastboot get detected properly. Heck, it just doesn't register correctly. At least for my xperia arc.
Which leads me to wonder, is the "fastboot not working" an issue only for the xperia arc, or an android issue in general? When I need to flash a different kernel, I end up using my work system (fortunately, it has win7).