The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/b5f2b54349ff6529aaeb267e7302fee232436300

commit b5f2b54349ff6529aaeb267e7302fee232436300
Author: Simon Glass <sjg@chromium.org>
Date: Wed Oct 17 19:20:24 2018

memtest86+: Build with gcc

Unfortunately memtest86+ does not build cleanly with clang. Use gcc for
now.

BUG=chromium:894539
TEST=emerge-grunt memtest86+

Change-Id: I77538dca8ed4d8364ab27a77b94927eaa6d63e32
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/1285009
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[add] https://crrev.com/b5f2b54349ff6529aaeb267e7302fee232436300/chromeos/config/env/sys-apps/memtest86+

Update:

memtest86plus is building:

https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/1290190/2

but it does not boot from depthcharge right now.

I thought I could run the memtest ELF file but that doesn't work.

I tried loading it as a flat binary to 0x10000 but no dice:

Starting altfw/memtest86 at 0x10000...ERROR: ram_map: request out of range (0x4+0x0)
ERROR: ram_map: request out of range (0x4+0x0)


Anyone have any ideas?

Did you try "cbfstool $thecbfs add-payload -n memtest -f memtest86.elf"?

That converts the ELF to SELF, a simpler format, and what depthcharge uses for the legacy payload, so you probably need the same.

Yes I believe that's what I'm doing. I uploaded the CL here:

https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/1292996/3/sys-boot/chromeos-bootimage/chromeos-bootimage-0.0.3.ebuild