My mntus.params should only call RUNME.sh if there is no RUNME.done, so it should behave identical to the original mntus.params that it replaced, with the benefit of not requiring different versions for each kindle model (where using the wrong one can brick your kindle).
As far as I can tell, the RUNME.done file is created BEFORE the RUNME.sh file runs, so rebooting while it is backing up mmcblk0p1.img SHOULD disable it, and mntus.params should continue as the normal version. It should reboot fine to diags again like it did with the previous (display only) RUNME.sh.
EDIT: Perhaps I need to change mntus.params to add a "sync" after "touch /mnt/us/RUNME.done", but before starting RUNME.sh, to make sure that the new "disable" file actually gets written to disk and is not just sitting in a cache in memory somewhere.
Can a more experienced kindle developer (or linux / upstart guru) suggest what may be going wrong as described in previous posts (people used this tool to gain diags access, but then later bricked it so only fastboot works, when using the "diagnostic messages" RUNME.sh posted above). ???