I know this is probably a little late, but if you still have the drive maybe you can still resurrect it!
I have flashed a few xboxes with ms25 ms28 and I have just got the same problem when using the 10 second trick
I got Erasing ... Erasing Chip..
after that when i turned on the xbox all i got was a flashing power light!, tried to do 10 second trick and wouldn't even see the drive at all!
so just before giving up and buying a new drive, i tried one more time, typed the mtk flash command and hit enter!, it showed me options 1 and 2,... 2 being my xtreme backup option on my via sata card and instead of turning off the xbox to do the 10 second trick, i just hit 2 straight away and POW it kicked it back into life and it started updating! woohoo!!!
All is ok now and boots just fine!!
hope this helps!