I managed to restore my Guru Plug using the above instructions. At first it seemed that the kernel was not working, it kept rebooting. Turned out that the plug was too hot; leaving it to cool down for a few minutes and then plugging it back in did the trick.
BTW, looks like you´ve sold us a useless device. What good is a plug computer if you can´t keep it plugged in because of overheating?