> I don't know, but maybe no one knows whether the region (before
> 0x100000) is safe? (or 0x100000 was just taken from original
> NetBSD/powerpc?)

I've been exploring this with OpenBSD's bootloader and I've found that
0x24000 (close to the original 0x20000) has not caused any problems in
OF 1.0.5 with INSTALL of 1.5.3 and 1.6.2. I believe there is an
exception handler installed around 0x18000, but this may not be true
with NetBSD. It would be interesting to find out just how low the kernel
could get loaded. 

> Anyway, even if we can use the area, we should move kernel TEXTADDR
> rather than to use it for bootloader because bootloader doesn't
> have to be preserved once after a kernel is loaded.

My next proposal would be to preserve the bootloader and use it to
restore any Open Firmware settings that were altered for the purpose of
booting NetBSD (after the call to OF_chain in boot.c). My thought would
be to not include this activity in the kernel itself, as it would be
machine specific. 

tim