>1) When I zero out the first meg or so of the disk (with dd from the
>NetBSD boot floppy), and then run Win95's fdisk and format, the disk is
>bootable.  NetBSD's fdisk claims the geometry is 149c, 255t, 63s.

Ok, so that says the BIOS is using 149/255/63 as expected.

>2) When I install NetBSD directly over the top of the setup in 1), sysinst
>gets the MBR geometry and sets stuff up.  I tell it to use the entire disk
>for itself.  But the hard disk is not bootable, for whatever reason.  

So, after booting from the floppy here, it appears the NetBSD fdisk
sees 1980/15/80!  And the below ...

>3: sysid 165 (NetBSD or FreeBSD or 386BSD)
>    start 63, size 2393622 (1168 MB), flag 0x80
>	beg: cylinder    0, head   0, sector  0
>	end: cylinder  970, head  11, sector  5

says the beg cyl/head/sector is NOT getting set correctly.

>3) If I re-run sysinst and tell it that the BIOS thinks the geometry is
>1024c, 16h, 63s, then it installs just fine and makes the disk bootable.

This then rewrites the MBR and most likely correctly sets the above stuff.
Could you send me the output of fdisk after step 3?

Thanks.

-- 
Phil Nelson                    NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu        !gifs: http://www.gnu.org/philosophy/gif.html
http://www.cs.wwu.edu/~phil