Comment 22 for bug 1437024

Another update on this:

I updated jolteon (the Lenovo x3550 M5 that was the original source of this bug report) with the latest firmware I could find (v.2.21, build TBE126Q, dated 2016-11-18) and reproduced the original bug. It appears to be unchanged, with one twist: At one point, the system was booting normally, so long as MAAS configured the system to use DHCP for ALL its Ethernet ports. After some changes to the system settings, though, it stopped working again even with those settings. I suspect that the PXE and MAAS DHCP-provided IP addresses synced up briefly, but then went out of sync again.

Also, the boot sequence on a failure looks something like this (taken from jolteon, the Lenovo x3550):

>>Start PXE over IPv4.
  Station IP address is 10.1.10.128

  Server IP address is 10.1.10.2
  NBP filename is bootx64.efi
  NBP filesize is 1169992 Bytes
 Downloading NBP file...

  Succeed to download NBP file.

 Downloading NBP file...

  Succeed to download NBP file.
Fetching Netboot Image
error: couldn't send network packet.

                             GNU GRUB version 2.02~beta2-36ubuntu3.12

   Minimal BASH-like line editing is supported. For the first word, TAB lists possible
   command completions. Anywhere else TAB lists possible device or file completions.

grub>

Note the "couldn't send network packet" message. This message isn't always visible (perhaps it flashes by too quickly to notice?). This is consistent with the Wireshark output, which shows no packets received by the MAAS server.

I've managed to get the Supermicro server to boot reliably. The trick for it is to configure it to PXE-boot from one of its 10 Gbps NICs rather than from its 1 Gbps NIC. The procedure for configuring the Lenovo to boot reliably is documented at https://wiki.canonical.com/CDO/HardwareCertification/LenovoxM5. This is tedious because of the Lenovo's complex firmware setup utility with many interacting settings.