[syslinux] chainloading syslinux from an EFI partition to an ext4

[Didier Spaier]

On 06/06/2015 13:14, Stoppa, Igor wrote:
> On 6 June 2015 at 14:03, Didier Spaier via Syslinux <syslinux at zytor.com> wrote:
>>
>>
>> On 06/06/2015 12:19, Stoppa, Igor via Syslinux wrote:
>>
>>> So I'd like to not put all the kernels/initrds in it, because when I
>>> update one of the OSes, I would also have to update the corresponding
>>> kernel in the EFI partition.
>>
>>
>> IIRC this is not possible (yet?) as kernels and initrd should lie in the ESP
>> alongside the EFI image(s) and the config file. But I am not sure, so if I
>> am wrong please someone correct me.
>
>
>>From what I understood, that's what you want to do if you want the EFI syslinux
> to boot your kernel, yes.
> But.
> What I'm trying to do is to have the EFI bootloader to chainload an
> ext4 partition
> where I have installed extlinux. The kernels and initrd lie alongside
> the extlinux bootloader.
>
> In a more schematic way:
>
> 1) the EFI BIOS loads the EFI syslinux
> 2) the EFI syslinux chainloads the extlinux that is on a separate partition
> 3) the extlinux loads the kernel & initrd that are colocated in the
> same directory
>
> point 2 is failing


I have no experience in chainloading but am rather pessimistic as I see 
this warning in http://www.syslinux.org/wiki/index.php/Doc/chain#file

"It is often convenient to load a file directly and transfer control to 
it, instead of the sector from the disk. Note that the <file> must 
reside on the SYSLINUX's partition."

Maybe you could get the expected result fiddling with the seg and sect 
options of chain, but I really don't know.

Didier