[syslinux] Problem booting from CF/SD cards and USB Flashdrives using syslinux

[c.lee111 at gmail.com]

On Fri, 24 Aug 2007, H. Peter Anvin wrote:

> c.lee111 at gmail.com wrote:
> >>
> > Well something  is going on that has to do with the geometry of SD/CF 
> > cards and USB Flashdrives and I don't think it all has to do with with 
> > the BIOS USB ZIP issue either. I'm tending to think Syslinux maybe 
> > is  touchy in reguards to what drive geometry (number of cylinders 
> > in particular) a usb SD/CF card or USB flashdrive is formatted with.
> > 
> > Like I said before it's pretty much the only thing that would explain 
> > why usb cards and flashdrives  I formatted to be bootable under windows 
> > 98 would boot, (and they weren't patitioned using zip drive or floppy 
> > geometry) but the same cards and drives wouldn't boot on the same 
> > machine using syslinux untill I went and changed the card or drive 
> > geometry to either 64 32 or 255 63 using mkdiskimage under linux, which 
> > basically changed the number of cylinders from being over 1024 to 
> > being under 1024.
> 
> SYSLINUX requires that the BIOS is self-consistent, that is, that it
> reports the same geometry that it itself expects to use -- except, of
> course, unless it is in LBA mode.
> 
> There seems, unfortunately, to be some BIOSes which say one thing and do
> another.
> 
> 	-hpa
> 

So you're basically saying that SYSLINUX is in fact pretty much affected 
by a 1024 cylinder bug. Basically if SYSLINUX encounters more than 
1024 cylinders on USB media on a machine that has a BIOS that's not 
"self-consistent", SYSLINUX becomes confused and doesn't know what 
to do next and therefore the USB boot process either aborts or crashes.

Chris.