[rescue] Q about sun2 boot flow

[Walter Belgers]

Hi Jan et al,

> On 7 Sep 2026, at 20:03, uix--- via rescue <rescue at sunhelp.org> wrote:
> this how I boot SunOS 3.x on my SUN 3/50:
> https://github.com/senjan/ndd/wiki/How-to-install-SunOS-3.5-on-a-Sun3-with-NDD
> I suppose Sun 2 would be similar.

Sound logical the way you set it up. Unfortunately, the sun2 does not do RARP/TFTP to bootstrap, it uses the ND protocol for the first boot stage as well (from ndp0).

I am trying to set up ndd to serve ndp0 (minor 0x40) with the correct file. This requires recompiling ndd to accept nd64. Using the SunOS 3.5/sun2 miniroot as the ndp0 disk (mimicking your approach) doesn't work. I also tried making a (small) 4.2 filesystem with just /boot and /vmunix, adding bootnd to blocks 1~15. That also did not work. I feel like I am close though.

There's also a trick I found: the SunOS 4.0.3 first stage boot loader (sun2.bb) can be loaded using ndbootd and then tftp can serve a 4.0.3 second stage (boot.sun2), which understands NFS and can mount a filesystem that contains /vmunix, which then gets loaded. That kernel will revert to ND after it's loaded so the / and /usr filesystems should be served using ndd. I had an image I created with both filesystem on one disk, and serving that via ndd (as nd0) had only / turn up. But it should not be too much work to figure out how to get this working. But using the complete boot chain from SunOS 3.5 (or 2.0 or 1.1), so only using ND, is what I'd like to get running.

Regards,
Walter.