Subject: Re: Prep bootloader
To: Jochen Kunz <>
From: Tim Rightnour <>
List: port-prep
Date: 03/10/2006 23:34:30
On 08-Mar-2006 Jochen Kunz wrote:
> I have to admit to be quite clueless in the bootloader department. How
> hard is it to build a bootloader that reads a kernel image file from
> FFS? I suppose most of FFS handling is in some kind of MI lib. So it may
> be "just a bit if glue code" to do the actual IO via firmware calls. Is
> there a firmware interface for device independent IO? (All I know is a
> bit OpenFirmWare and the hp700/hppa PDC.)

So.. I've done some investigation on the bootloader, and come up with something
rather disturbing.

The PReP spec quoteth:
        "Conventional firmware must not export any entry point for call-back to

This means we are essentially fscked.  When they say "conventional firmware"
they mean prep firmware, as opposed to actual Open Firmware.  A second stage
bootloader would essentially need a standalone scsi driver, (possibly requiring
a PCI layer) a standalone ISA IDE driver, and maybe even network support.

All of this means.. I think we are back to my original idea here.  We just need
to make mkbootimage as painless as possible to use, and train sysinst to use it.

Tim Rightnour <>
NetBSD: Free multi-architecture OS
Genecys: Open Source 3D MMORPG: