bunjibear,
first you can try your PRS in "PRS+ SafeMode".
Shutdown or reset, connect to USB and restart.
You get the USB-transfer screen.
Disconnect.
Unalterd Sony Firmware without PRS+ will start up.
So you can check if your problems are PRS+ related.
There should be no need to tweak any installer, try the unistaller from the project-page
here:
PS: please edit your personal info to show the 650, too