acer iconia held after system update

I took part of this post from XDA that was relevant to you.
Also when on this site go to DEV section to find the rom you need and info on fixing this.

http://forum.xda-developers.com/showthread.php?t=1238020&highlight=You+Tube+-working+on+a500



if ever you have a problem with an acer iconia product, i would suggest you should use a stock acer iconia 3.1 rom.

you can find it in the dev section XDA Web Site
also don't forget to get the zip decryption tool, you can also find it in the dev section.
then once decryption is done, extract the update.zip and put it on the external sd card (which i hope you have)

once on it put the card into the appropriate place in the acer iconia

then you hit volume+ (volume plus) and the power button until it restarts. after release the power button but keep you finger int the volume+ until you see a message that it is formatting data cache etc..

then you are back to stock ACER and you take it from there to patch.

 

[OTA] Full Package and Update - xda-developers
You can try this link and use the tool you find here.
I'm not really sure which full update you should use but it all on this page. Also sign up on this forum and go to either Q and A or General and state your problem.There more equipped to help you as m still a rookie.