SNP failure when chainloading from U-Boot

[ljfranklin]

Issue

Using the setup below, I'm trying to chainload iPXE from U-Boot on a small ARM32 board (ODroid MC1). iPXE is able to see the SNP interface with `ifstat`, but running `ifopen net0` shows `NETDEV net0 failed to receive 0x0: The socket is not connected` and the iPXE shell freezes. Full log is shown here and iPXE config page is here and here.

Any tips for debugging this further? Thanks y'all!

Setup

Board: ODroid MC1
CPU: ARM32 Samsung Exynos5422
iPXE build: bin-arm32-efi/snp.efi with lots of DEBUG enabled, script
iPXE source: latest master but had to disable a couple optional features to avoid freezes, diff
U-Boot build: script

[ljfranklin]

Cross-posting to GitHub issue: https://github.com/ipxe/ipxe/issues/149