I'm not sure how to go about flashing even the stock img. From some of the guides I've seen, you need to either be rooted or in the menu that first gets displayed when powered on by holding Power and Vol-, but I can I can't seem to get to that menu. Even if I attempt to hold Power and Vol-, it only comes up with that Android with the circling cage that says "Erasing...".
That freezes after several minutes and eventually brings me to the menu where I can reboot, factory reset, and all that. I could be missing something, but I don't believe I can get back to the "original" bootloader menu (or whatever it's called) that has the other options from there.