[PLUG] Sony Vaio not booting from optical drive

[Rich Shepard]

   Have an older Sony Vaio portable (probably > 5 years old) that has been
quite reliable even though the battery is worn out. Today I migrated it from
Slackware-14.1 to -14.2 with a new installation after chaning partition
formats from ext3 to ext4. It booted after this instillation.

   Then I upgraded all the patched packages including the new 4.4.88 kernel.
But, I made a mistake in the initrd command line and the kernel paniced when
I tried rebooting.

   Turned off the machine and inserted the distribution DVD which would boot
and let me access the hard drive to fix the initrd in /boot and re-run lilo.
Except the system will not access the optical drive. The POST splash screen
appears and there it sits. While I made and ate dinner it tried to boot from
the hard drive with the same kernel panic result.

   My web search taught me that pressing the Assist key with the power off,
and holding it down while turning on the power is supposed to display a menu
that will let me access the BIOS settings (which should have the optical
drive first for booting as that's what it's done in the past. This evening,
there's no joy: pressing and holding the Assist key while turning on the
power does nothing; the POST splash screen dispays and nothing happens.

   I suspect that a developing hardware failure was invoked by the kernel
panic; I may be completely wrong on this.

   Is there anything I might try to get the system to boot from the dvd in
the optical drive? That would allow me to remake the initrd and that should
allow the system to boot if the hardware's OK.

   Advice and ideas are solicited.

Rich