Hi xu peng,
Did you use an Innvo PleoRB operating system to upgrade your Ugobe Pleo? On this forum the Ugobe Pleos are refered to as "Classic" Pleo.
There is some confusion as both PleoRB and Ugobe Pleo have a version 1.1 OS (the Ugobe version is refered to as LifeOS just to add some more confusion, while the PleoRB just had a firmware update)
In the case you have a Ugobe Pleo, your best chance to restore your bricked Pleo is to use the POP (point of purchase OS) from the Classic pleo download section, that should restore operation to with just the demo mode software.
The second step (in my humble opinion) would be to install the upgrades in number order only when I have ensured that the battery is in good condition. A shutdown due to low battery during update can cause lots of problems.
Cheers!
Peter