ive done it a million times, id do it, just amke sure you do it and a disc cleanup and do both and test them out, make sure you have all of the drivers+firmware you want to do also, cause sometimes when i format my jb3, it has a firmware problem, no biggie tho, bust out the usb cable(cause mine doesnt reload the OS w/ the 1394...anyway) and 'upgrade firmware' from the comp, turn off/on a few times to see if it gives you that error, and youre golden
sounds harsher than it is