Oops, that's MemFree+(Buffers+Cached)*0.9 of course

If the check is dropped (i.e. by using --force or commenting out), grml2ram
succeeds as expected.

However isn't the RAM check just a sanity check after all?
If so, something like MemFree-(Buffers-Cached)*0.9 > grmlsize would make sense.

Hm, what happens if you modify /usr/sbin/grml2ram to use "Inactive" instead and
what happens if you drop the check overall?

Because I'm not sure that "Inactive" would really help, example output from one
of my systems:

# grep MemFree /proc/meminfo  
MemFree:         3568244 kB
# grep Inactive: /proc/meminfo
Inactive:        2803648 kB
# free -m
             total       used       free     shared    buffers     cached
Mem:         15784      12357       3426          0       1733       5297
-/+ buffers/cache:       5326      10457
Swap:         2045         94       1951
#

grml2ram fails reporting that there is too less free RAM despite there is plenty.

Problem: the MemFree entry of /proc/meminfo is parsed which is usually small
because free memory is used by buffers and caches.

Sample:
# grml2ram
 * Sorry, not enough free RAM (246276kB) available for grml-image (387712kB).   
# free
             total       used       free     shared    buffers     cached
Mem:       6126996    5880344     246652     239016    4634320     290508

Probable fix:
Parse a different value from /proc/meminfo, like Inactive?