Make sure to update your USB drivers before you do anything
Created custom_update_signed.zip had trouble getting _hack_recovery.zip to work correctly. Once updated USB drivers it worked and I applied the custom update, but now I don't have root and I don't see tempsu or busybox files anywhere on the system.
Is it possible to rollback? Can custom recovery help me here? Can I install signed 3.x rom?
At least I have a working ICS tablet.