[syslinux] Fedora 21 extlinux 6.03 boot failure

[Andrew J. Schorr]

Hi,

I discovered a very strange situation.  I have 22 systems running Fedora 21
(F21) with bundled syslinux-extlinux 6.03.  On one of those systems, I am
having trouble booting.  This machine was upgraded from Fedora 19 (F19), so can
boot either the new or the old O/S -- F19 is on one disk partitition, F21
is on another, and there's a shared /boot partition.  On this one machine,
when I try to boot into F21 using the F21 version of extlinux, the system
resets (reboots) right at this point:

   Loading /vmlinuz-4.0.5-200.fc21.x86_64... ok
   Loading /initramfs-4.0.5-200.fc21.x86_64.img...ok

And then it reboots.  If I instead choose the F19 partition from the extlinux
boot menu, it boots successfully into F19.  I tried this with 2 different
versions of the F21 kernel (3.19.7 and 4.0.5), and I observed the same
behavior.

If I boot up into F19 and install the F19 version of syslinux-extlinux
(4.05), I can then boot successfully into either F19 or F21.

To summarize: F21 extlinux 6.03 can boot only the F19 partition,
but F19 extlinux 4.05 can boot either F19 or F21.  The same setup works
without any troubles on 21 other computers, but on this particular one,
the F21 extlinux cannot boot the F21 kernel/initramfs.

The machine in question is very old -- it's an Intel S5000VCL motherboard
with a Xeon E5420 CPU and 1 GB of memory.  I don't have any others with
this same motherboard.  But I do have older systems with less memory that
work fine (for example, an Intel SE7230NH1LX motherboard with
a Pentium 4 cpu and 512 MB of memory).

Is there any way of troubleshooting this?

Thanks,
Andy