[syslinux] "--once" getting stuck

[Giulio Orsero]

RHEL5.3, syslinux 3.75

I tested syslinux "--once" functionality on a vmware image and all was
working as expected, then I tried it on a real system and it failed: it got
"stuck", it had effect at every boot, I could see the cmdline was never
deleted from extlinux.sys.

The vmware image used during testing has a virtual IDE disk (/deb/hda), the
real system has SATA-AHCI (/dev/sda).
Then I created a new vmware image with a SCSI disk (lsilogic) and the same
issue came up.

I'm using
	# extlinux --once="linux test1234" /boot/extlinux
then I verify that test1234 shows up twice in extlinux.sys as it should,
reboot, see that cmdline has test1234, but the string test1234 is still in
extlinux.sys and so at the next reboot (and forever) the cmdline will
contain test1234.

I can reset the cmdline successfully with
	# extlinux -O /boot/extlinux.

What can I do to debug this (working on IDE, failing on SCSI)?

Thanks
-- 
giulioo at pobox.com