Re: 43p: Install kernel boots, generic not

[This mail was also posted to gmane.os.netbsd.ports.prep.]

On Sun, 14 Jul 2019 17:59:55 +0200 (CEST), Ulrich Teichert wrote:

> Hi,
> 
>> On Sat, Jul 13, 2019 at 06:48:04PM +0200, Ulrich Teichert wrote:
>> > I haven't seen a bootloader for prep in the NetBSD tree. Either
>> > yaboot (which does not work out of the box:
>> > https://www.netbsd.org/ports/macppc/faq.html#yaboot) or grub2 will be
>> > candidates, but I think I'll start with yaboot - it's just so much
>> > smaller.
>> 
>> but you quoted:
>> 
>> >> NetBSD/prep BOOT, Revision 1.9 (Sun Jul  7 15:18:27 UTC 2019)
>>   
>> so it has to exist ;-)
>> 
>> See src/sys/arch/prep/stand/README
> 
> Yes, right.... What I wanted to say was: I haven't seen a bootloader in
> the NetBSD tree which can circumvent the firmware boot limit of ~2MB per
> file loaded (at least on 43p boxes).
> 
> The experiments in the existing bootloader to access the SCSI controler
> after load to bypass that limit were more or less causing the whole trip
> into NetBSD-prep for me, as it turns out ;-)
> 
> Do you know if yaboot would be able to act as a secondary bootloader to
> load a kernel > 2MB directly from a NetBSD partition? Or should I try
> grub2? Fumbling with the SCSI controler in the bootloader without
> hardware documentation will be a waste of time, as I've already found
> out. I wasn't able to understand what interrupt/PCI/whatever setup was
> missing to get this working.
> 
> CU,
> Uli

Hello, I was re-reading this thread and found the data manuals for the 
integrated SCSI controllers in at least two of the PReP machines.
7248-(100,120,132) uses this one:
https://archive.org/details/
bitsavers_ncrsymbiosSCSIIOProcessorDataManualMay1993_9687379/page/n7/mode/
1up
7043-140 uses this one:
https://archive.org/details/bitsavers_ncrsymbiosaManualVersion3.0_1214361