[syslinux] Boot 32GB Multi-partition Flash as USB-ZIP

[Ray Rashif]

I have a Pentium 4 machine that does not boot from my 32GB SanDisk
Cruzer. Its first partition is 24GB and FAT32, to serve as
cross-platform storage. There is a second partition of 7GB in EXT2
which is bootable and contains a Linux system armed with syslinux
(extlinux). This works fine booting off of recent laptops and desktops
alike.

This particular desktop has in its BIOS everything related to USB and
booting configured well. "USB Boot" is "Enabled". There is a "Legacy
USB Emulation" or something along those lines set to "Full-speed", and
"High Speed USB" is "Enabled". Changing these has no effect.

In the boot options, there is only the floppy under "Removable
Storage". The SanDisk is successfully detected as a Hard Disk and has
to be moved up in the list. In this case, the SanDisk gets first
priority.

The BIOS does get it right, because I see a syslinux error flashing
by: "Missing operating system"

That's one quick message, and the machine continues on to the next
available boot medium (which is the primary hard disk of the machine).
Of note is the fact that there are 2 hard disks, 1 a SATA and the
other an IDE.

As such, I suspect this has to do with the BIOS not being capable of
booting off of the large flash drive. I also tried creating a (third)
separate 150MB FAT16 boot partition, but that did not help one bit. At
this point I think this has everything to do with "USB-ZIP", although
there is nothing related to this in the BIOS.

The problem now is that the documentation on this is scarce,
especially for drives larger than 1GB. I want to be able to have a
FAT32 and an EXT2 partition, aside from the "fourth" ZIP-compatible
one. This partition #4 would be in my case a small bootable partition.
As I understand, mkdiskimage would take the entire disk. Or am I
wrong?

I would like some guidance on how I should go about making this possible.


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