Thanks for reporting and thanks also for the patch!

We've reworked the grml_cleanup_chroot script (into much more sane config/scripts with 
FAI's class features) so it actually doesn't even look at the most recent kernel version 
any longer the way it used to do. So your issue should be fixed when upgrading either to 
the current git version of grml-live or just waiting for the soon to come upload.

Marking this issue as fixed-in-git for now, if you notice any further issues please let us 
know.

Thanks!

regards,
-mika-