I would like to disable the touch screen with the VU5A touchscreen running on a C2. I see that there is an option in the boot.ini to disable touch with the VU7. However, when I set setenv disable_vu7 "true". It doesn't work for the VU5A.
Maybe set it to setenv disable_vu5 "true"?
You should be able to blacklist loading the drivers for the touchscreen.
and put the following code in it.
#Do not load the vu5a/vu7a touchscreen input drivers on boot.
this should be enough to stop the touchscreen drivers from loading and disable touch input.