[syslinux] "isolinux.bin missing or corrupt" when booting USB flash drive in old PC

[Ady Ady]

> 
> The computer has a HDD mobile rack.  I removed the HDD when testing the
> Debian installer image on a USB flash drive.  So, the only drive other
> than the USB flash drive under test was the optical drive.
> 
> 

In my last email, I forgot to emphasize the following generic 
procedure.

In the BIOS setup screen(s), one set of options are intended for 
sorting the boot order according to type of devices (CD-ROM, HDD, 
floppy...).

There is _another_ set of options, usually on the first (or the main) 
setup screen. The BIOS detects a list of devices currently connected to 
each PATA/IDE/SATA port. The detection also varies, depending on 
additional settings such as "legacy/raid/ahci/sata", or even "pio/dma" 
mode, meaning that the same devices might be detected and _listed_ 
within the BIOS main screen when using some of these settings, whereas 
they won't be listed while using different BIOS settings.

With your USB device connected and the computer powered off (as in 
completely shut down), power up and get into the BIOS setup screen. In 
the main screen, the first device, connected to the first, detected 
(P)ATA/IDE port, should be your USB device, as if it were to be 
identified as a regular HDD. This is different than the boot _order_ 
screen.

If the main screen in your BIOS can list the USB device as the first 
device in the list, and it can also be set as the first device in the 
boot order settings, then  the chances of booting successfully can 
increase.

This procedure is independent of the potential 32KiB limitation for 
isolinux.bin for certain BIOS implementations. This potential 
additional issue can still be an impediment to boot in certain systems 
anyway. The same goes for other potential issues.

Yet, if the BIOS cannot list / detect the USB device as if it was a 
common HDD (UNrelated to the boot order, just in addition to it), then 
the chances for a successful boot are diminished.

Regards,
Ady.