[syslinux] Sysinux 6 will not boot ISOs on BIOS (i.e. pre-UEFI) systems

[Thomas Schmitt]

Hi,

Gerardo Exequiel Pozzi wrote:
> Looks like there is something beyond LBA 65535 (As Mattias confirmed)

I wanted to ask him now, whether this was already with
version 6. 
But meanwhile he reported that it was 5.


> I can push isolinux.bin (4.07) to a really high LBA address and boot
> without any issue. (Load LBA: 2048034 (0x001f4022)) ~4G

This is riddling, given the statement of hpa that the
boot images are identical up to the point where Carl's
boot procedure fails.
There seems to be some loophole in the identity.

Another possibility could be that not the whole address
range above 128 MB is poisonous, but only particular
intervals.
Gerardo: did you really try 4.07 with exactly the same boot
image LBA as 6.02 ?

I fail to imagine a way how the boot image size could make
a high LBA poisonous. But well, if the firmware is mad ...

hpa: How much can we cut off a isolinux.bin so that the
early boot stage up to the problem still should work ?
If the first 12 blocks suffice, then Gerardo could make
a test with the same size as in SYSLINUX 4 (with expected
failure at some later stage).


Have a nice day :)

Thomas