Re: DVD does not boot.
> My laptops are all old HP's and Dell's.
> They all have legacy bios.
That's hard to explain. If you dd the ISO image to a thumb drive and
offering this drive to BIOS, then BIOS will run the x86 machine code
in the MBR at the very start of the ISO.
With SYSLINUX/ISOLINUX this machine code has the only task to load
the first 2048 bytes of the El Torito Boot Image for BIOS and to
start it at the same byte address as the El Torito Boot Catalog tells.
When getting to see a DVD, BIOS is supposed to look into the Boot Catalog
and to load the same first 2048 bytes of the El Torito Boot Image for
BIOS. Start address for the program run is supposed to be the same as
used by the MBR code.
Something must derail on your machines in this case.
Do you know any publicly downloadable GNU/Linux ISO image which boots
from DVD on these machines ? If so, please tell the URL.
Maybe i can spot some difference in the boot records.
Have a nice day :)