Syslinux - Aug 2003 - syslinux-2.05 boot floppy failures, size related?

I have occasional problems booting kernel boot floppies
made with syslinux-2.04/2.05. The symptom is that syslinux
loads an initial part of the kernel image and then halts with

Boot failed: please change disks and press a key to continue.

Observations:
1. It's not a media problem. I've switched floppies and
    reformatted them, but the failure persists.
2. It's not a BIOS problem. The latest image that failed
    does so on three very different PCs.
3. The problem appears to occur for specific image sizes.
    The latest failed bzImage is 947503 bytes, but enlarging it
    by including more stuff in the kernel allows syslinux to
    boot it. (I've booted 1200K+ images often, but syslinux
    seems to have problems with around 900K+ and 1100K+ images.)
4. syslinux -s makes no difference at all.

I've put my latest failed bzImage and corresponding 2.6.0-test3
.config in http://www.csd.uu.se/~mikpe/linux/syslinux205bug/,
in case anyone can debug it. I tried looking at syslinux' source
but it's a big pile of assembly so I'm lost there...
--
Mikael Pettersson (mikpe at csd.uu.se)
Computing Science Department, Uppsala University

Mikael Pettersson wrote:
> 
> Observations:
> 1. It's not a media problem. I've switched floppies and
>    reformatted them, but the failure persists.
> 2. It's not a BIOS problem. The latest image that failed
>    does so on three very different PCs.
What three different PCs?
> 3. The problem appears to occur for specific image sizes.
>    The latest failed bzImage is 947503 bytes, but enlarging it
>    by including more stuff in the kernel allows syslinux to
>    boot it. (I've booted 1200K+ images often, but syslinux
>    seems to have problems with around 900K+ and 1100K+ images.)
> 4. syslinux -s makes no difference at all.
> 
> I've put my latest failed bzImage and corresponding 2.6.0-test3
> .config in http://www.csd.uu.se/~mikpe/linux/syslinux205bug/,
> in case anyone can debug it. I tried looking at syslinux' source
> but it's a big pile of assembly so I'm lost there...
Please put floppy images instead.  That way I might be able to reproduce 
the failure.

	-hpa

On Wed, 20 Aug 2003 10:41:00 -0700, H. Peter Anvin
wrote:
>Mikael Pettersson wrote:
>> 
>> Observations:
>> 1. It's not a media problem. I've switched floppies and
>>    reformatted them, but the failure persists.
>> 2. It's not a BIOS problem. The latest image that failed
>>    does so on three very different PCs.
>
>What three different PCs?
Yesterday I tested another machine so now there are four:
ASUS P4T-E P4 mobo, BIOS 1007 (latest non-beta)
ASUS P3B-F PIII mobo, BIOS 1008 Beta4 (latest one)
Dell Latitude CPi PII laptop, BIOS A12 (latest one)
Gigabyte GA-60XT-A PIII-Tualatin mobo, recent BIOS

I can test three more machines this weekend.
>> 3. The problem appears to occur for specific image sizes.
>>    The latest failed bzImage is 947503 bytes, but enlarging it
>>    by including more stuff in the kernel allows syslinux to
>>    boot it. (I've booted 1200K+ images often, but syslinux
>>    seems to have problems with around 900K+ and 1100K+ images.)
>> 4. syslinux -s makes no difference at all.
>> 
>> I've put my latest failed bzImage and corresponding 2.6.0-test3
>> .config in http://www.csd.uu.se/~mikpe/linux/syslinux205bug/,
>> in case anyone can debug it. I tried looking at syslinux' source
>> but it's a big pile of assembly so I'm lost there...
>
>Please put floppy images instead.  That way I might be able to reproduce 
>the failure.
Done. The file is 'fdimage' at the URL listed above. It was
produced on RH9 using mtools-3.9.8-7 and syslinux-2.05.

/Mikael