[syslinux] EXTLINUX: Reading the extlinux.conf but can't find Kernel

[H. Peter Anvin]

Dan Keating wrote:
> Hi Folks,
> 
> OK - I'm not entirely new to Linux but I'm certainly not great on the 
> boot process. What I'm trying to achieve is to boot from an external USB 
> HDD (not flash drive) using EXTLINUX.
> 
> I've run an installation against the disk using a VM. The disk was 
> partitioned as follows:
> 
> /dev/sda1 = /boot (bootable)
> /dev/sda2 =/swap
> /dev/sda3=/ (i.e. root)
> /dev/sda4=/dos
> 
> sda1 and 3 are formatted as EXT3 .. sda4 is FAT32.
> 
> As far as I can see, I've followed the instructions correctly and 
> initialised extlinux against the /boot/extlinux directory I've created. 
> MBR has been copied to /dev/sda
> extlinux.conf has been created and I know that it's being read at boot 
> time (I left a SAY command in the file which appears at boot).
> 
> However - I always get the message returned "Could not find Kernel 
> Image" then the path I specify to my kernel.
> 
> My understanding is that this will be the vmlinuz entry in the /boot 
> directory (which in my case is vmlinuz-2.6.20-15-server). So I've 
> specified /boot/vmlinuz-2.6.20-15-server as the value for my 
> extlinux.conf kernel parameter but it doesn't seem to be recognised.
> 
> It's obvious that I'm missing something here - and it's probably a hole 
> in my understanding of how this should work - but if anyone can help 
> plug that gap then please help.
> 

Yes, the problem is that /boot in your case is the root of a filesystem, 
so the file that is called "/boot/vmlinuz-2.6.20-15-server" in your 
filesystem is called "/vmlinuz-2.6.20-15-server" as far as extlinux is 
concerned.

If you make a relative filename it will be relative to /boot/extlinux, 
so you could also specify it as "../vmlinuz-2.6.20-15-server" if you'd 
prefer.

	-hpa