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

Mattias Schlenker ms at mattiasschlenker.de
Mon Nov 25 11:11:02 PST 2013


Am 25.11.2013 12:40, schrieb Thomas Schmitt:
>
> On my own test system, a high address (263921) and 6.02 work fine.
>
> So we have some ingredient in the boot firmware, and some other
> in a difference between SYSLINUX 6.01 and 4.07.
>
> The reported symptoms differ slightly:

In September Thomas and I discussed this topic off the list regarding 
Isolinux 5.0x after some colleagues signalled trouble booting the merged 
image of a rescue CD with further DVD content (the issue: I prepared a 
rescue CD that worked fine everywhere, when merging this CD with a few 
thousand files and re-named boot files to a DVD, it stopped booting on 
some machines). On all of my test systems everything worked even with 
high LBAs while the troubles my colleages had were as described: ETCD 
disk error plus halt, reboot or just hanging systems. After comparing 
the images of the rescue system alone with the merged DVD we noticed the 
different LBAs of isolinux.bin. When everything booted fine on every 
machine after moving isolinux.bin well within the LBA 65.535 limit we 
stopped investigating and moved on. Since the problem just occured on 
some BIOSes and was fixed after moving isolinux.bin to low LBA we 
thought the sole problem was the BIOSes.

If someone is suspecting a strange interaction between changes in 
Isolinux from 4.0x to 5.0x and buggy BIOSes we might however try to 
narrow down the factor Isolinux. On December 11th I will be at the 
Springer offices in Hamburg again where I can test some prepared images 
on affected hardware and document BIOS vendors and versions (we 
identified four out of twenty machines in the test pool, built between 
2005 to 2010) to be affected. I am however not very keen to do so, 
because: With a few hundred thousand bootable ISOs on computer magazines 
in Europe and Southern America that I prepare every year we run into the 
weirdest BIOS and UEFI issues. Sometimes after releasing a DVD I get 
three complaints of the same boot failures the first day. I then assume 
to have run into a widespread problem, assume 50 times more people 
affected, create a workaround and ... end up with seven downloads even 
after widely propagating the fix.

So my opinion is: Leave this strange interaction uninvestigated, remind 
users to force a sort order that moves all isolinux related files to low 
LBAs when building ISOs and move on, it is not worth the time. I will 
gladly write a section on the issue for the xorriso man pages (and the 
syslinux wiki) but we should not go any further as long as the problem 
does not occur with boot images located lower than 65535.

Regards,
Mattias

PS: Thomas, might I call you during the next days? POTS style?

-- 
Mattias Schlenker - Redaktion + EDV-Beratung + Linux-CD/DVD-Konzepte
August-Bebel-Str. 74 - 04275 LEIPZIG - GERMANY

Bitte fuer geschaeftliche Telefonate vorzugsweise die VoIP-Telefonnummer
+49 341 39290767 verwenden, da ich diese aufs Mobiltelefon routen kann!



More information about the Syslinux mailing list