I'm going slightly insane trying to get NetBSD working on a Soekris 
4801.  I'll post the different problems separately.

First, I can't get PXEboot working.  It downloads the first-stage
bootstrap (pxeboot_ia32.bin), but it can't seem to load
netbsd-INSTALL.  tcpdump shows that it's being requested:

   20:24:55.283315 00:00:24:c4:f4:40 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 65: IP (tos 0x0, ttl  20, id 37, offset 0, flags [none], length: 51) 192.168.2.240.2480 > 0.0.0.0.69: [udp sum ok]  23 RRQ "netbsd-INSTALL" octet 
        0x0000:  ffff ffff ffff 0000 24c4 f440 0800 4500  ........$..@..E.
        0x0010:  0033 0025 0000 1411 e2fd c0a8 02f0 0000  .3.%............
        0x0020:  0000 09b0 0045 001f f673 0001 6e65 7462  .....E...s..netb
        0x0030:  7364 2d49 4e53 5441 4c4c 006f 6374 6574  sd-INSTALL.octet
        0x0040:  00          

and /var/log/messages shows that tftpd seems happy:

Oct 14 20:24:55 bigboy dhcpd: DHCPDISCOVER from 00:00:24:c4:f4:40 via bge0
Oct 14 20:24:55 bigboy dhcpd: DHCPOFFER on 192.168.2.240 to 00:00:24:c4:f4:40 via bge0
Oct 14 20:24:55 bigboy dhcpd: DHCPREQUEST for 192.168.2.240 (192.168.2.79) from 00:00:24:c4:f4:40 via bge0
Oct 14 20:24:55 bigboy dhcpd: DHCPACK on 192.168.2.240 to 00:00:24:c4:f4:40 via bge0
Oct 14 20:24:55 bigboy tftpd[12176]: 192.168.2.240: read request for netbsd-INSTALL: success

But nothing happens after that.  I get err 60 -- ETIMEOUT, I believe -- 
on the Soekris console.

		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb