Hi,
I don't know whether its the same but when I asked a similar question about the Jornada 680 I was told to try Small Tweak -
http://tillanosoft.com/ce/stweak.html - which has an option to allow PocketIE
(and other apps from what I've found
) to display 65,535 colours.
Unfortunately HP don't seem to offer their updated "Vibrant Color Display driver" for the 820. You could try the one for the 680 and see if it makes a difference, I honestly don't know what it might do though
(if anything!
).
Don't think you can change anything else, the only way you might get more is by ditching WinCE and trying one of the Linux derivatives?
Hope this helps,
Pete.