HP laptop hanging at iPXE initialising devices...

[robinsmidsrod]

If you're using isc dhcpd you can setup a special host entry for that laptop that will override the generic one you have for all machines. And the name undionly.kpxe is not magical. You can rename it to ipxe-undionly.kpxe and gpxe-undionly.kpxe and use them side-by-side. With this you should have a workaround that allows you to keep everything working with a bit of more complexity in your DHCP setup.

What would be great is if you could do a git bisect, http://ipxe.org/howto/bisect, to try and find the commit that made your HP laptop unbootable. I would suggest you start with the gpxe/ipxe fork commit, which I believe is this one: 8406115 ([build] Rename gPXE to iPXE from 2010-04-19). It would be useful if you also send the information git bisect gives you to the mailing list, as some developers pay more attention to that one than the forums.