[ipxe-devel] iPXE does not boot OpenBSD ELF kernel

Michael Brown mbrown at fensystems.co.uk
Fri Mar 1 16:57:43 UTC 2013

On 28/02/13 12:27, Alexander Frolkin wrote:
> I'm trying to boot an OpenBSD kernel from iPXE, it's bsd.rd from OpenBSD
> 5.2 amd64 (ftp://ftp.openbsd.org/pub/OpenBSD/5.2/amd64/bsd.rd).  'file'
> says:
>    bsd.rd: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped

OpenBSD 64-bit kernels are 64-bit ELF binaries, and require a bootloader 
prepared to set up 64-bit long mode.  iPXE doesn't have any support for 
this.  Ideally, OpenBSD would ship kernels in a standard format such as 
Multiboot, which starts executing in 32-bit mode.

> I've also just tried booting a 32 bit kernel, and this gives a different
> error:
>    Could not boot: Requested memory not available (http://ipxe.org/46038101)

iPXE detects the 32-bit kernels as ELFBOOT, but they aren't actually in 
ELFBOOT format since they use non-flat addressing.  Again, it would be 
great if OpenBSD shipped kernels in a standard format, but they don't.

You can probably find some way around this, e.g. using sanboot to boot 
an OpenBSD .iso image, or using pxelinux.0 as an intermediate bootloader.


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