Comment 13 for bug 927781

Hope Robbie does not mind my inserting this from an email of his:

....

Summary

pxelinux emulation on ARM does not match the behaviour of pxelinux.0 on
Intel, even in areas that are not architecture-dependent. This means
that developers working and testing on Intel push stuff that they expect
to work, and it doesn't. This costs us considerable time dealing with
the impedence mismatches.

Things to Fix

Ideally, everything. Someone could do an audit of U-Boot's pxelinux
emulation as it appears in upstream trunk, compare it to pxelinux
documentation and construct a complete list of missing features and
behaviour.

Specific Things That We've Noticed

This is based on the U-Boot supplied to us by vendors, rather than
upstream trunk.

 * U-Boot does not understand "localboot", which is important for MAAS'
   current mode of operation.

 * U-Boot ignores DHCP options 208 through 211. LP: #927781, RFC5071.

 * U-Boot cannot parse a configuration in the following form that is
   valid in pxelinux, due to limited menu support:

 DEFAULT menu
 PROMPT 0
 MENU TITLE foo
 TIMEOUT 1
 ONTIMEOUT ubuntu-enlist

 LABEL ubuntu-enlist
  kernel bar
  MENU LABEL ubuntu-enlist
  append baz
  ipappend 2
 MENU end

Robie