Any luck getting it fixed yet? I did a manual update on my Voyage and it behaved properly... is there any chance power was interrupted or changed or something during the upgrade process? You mentioned doing a 40 second reset - is the kindle responding to holding the power button down at all? Are you still looking at the tree, or are you looking at a blank screen (powered all the way down)?
When you updated, did it ever show the "update successful" screen, then go into it's restart process - is that where it froze? One thought might be pulling power altogether - you can wait until the battery dies, or to be faster, pull the back cover, and unplug the battery for a few minutes, then plug it back in and see if it comes back. There are instructions and pictures showing how to take it apart here:
https://www.ifixit.com/Teardown/Kind...Teardown/32278
Looks to be very easy compared to many devices (like newer iPod nanos...)