Resource: https://www.netbsd.org/docs/network/netboot/rbootd/#linux

Prequesites

This guide was written for a PC running Arch-Linux. Similar packages should exist for Debian. No idea about Windows

Boot into netbsd

Install tftp and dhcp server

sudo paru -S uftpd dhcp

setup dhcp config

/etc/dhcpd.conf

allow bootp;
default-lease-time 600;
max-lease-time 7200;
INTERFACESv4="enp7s0f1";

# This will tell the box its hostname while booting:
use-host-decl-names on;

subnet 192.168.1.0 netmask 255.255.255.0 {
		option routers 192.168.1.1;
		option domain-name "foo.com";
}

host vodka {
		hardware ethernet 08:00:09:5C:19:0E;
		fixed-address 192.168.1.22;
		filename "netinstall.lif";
		option root-path "/exports/client";
}

Here the HP PC with the mac 08:00:09:5C:19:0E will get the ip 192.168.1.22, the hostname vodka und attempt to boot the file netinstall.lif from your tftp server meaning the file you specify here will need to exist in /tftpboot on your netboot server. Make sure to adjust the MAC address (found by typing lan in the HP BOOT_ADMIN loader)

Get a lifimage

A lifimage of the NetBSD installer can be found at https://cdn.netbsd.org/pub/NetBSD/NetBSD-10.0/hppa/installation/

Place it into /tftpboot on your netboot server

Start the tftp server

# uftpd -n -o ftp=0,tftp=69 /tftpboot/ This will start a tftp server which serves the files in /tftpboot

Configure your ethernet interface

The DHCP config states the subnet 192.168.1.1/24 So set your ehternet interface to 192.168.1.1 with the netmask 255.255.255.0 and 192.168.1.0 as gateway. This will make you unable to use your local network over ethernet and is intended for use to connect directly to your hp workstation. If you wanna integrate it with your home network you must modify the dhcpd.conf file mentioned earlier accordingly

Restart dhcpd

# killall dhcpd # dhcpd It should say listening on... If it doesn't say that you misconfigured your ethernet interface and the dhcp server did not find a subnet it is serving which matches your interfaces ip.

Boot the workstation

On your workstation use search lan to search for bootable lan media on your network. Make sure your netboot server and workstation are connected via ethernet. After you found a bootable media boot with boot lan

Further stuff to do

Apparently BOOTP can tell the PC to use a NFS networked filesystem and mount it upon boot. I wrote down that it has something to do with nfs-utils