FreeBSD-10-STABLE hangs when booting from BeagleBone Black eMMC

[Winston Smith]

On Sun, Apr 27, 2014 at 1:16 PM, Ian Lepore <ian at freebsd.org> wrote:
> I only have a BBW, no BBB to play with, so I can't help too much with
> this.  I can say however that if you're having trouble with reading the
> eMMC in ubldr, the trouble is probably in u-boot.  U-boot is still in
> memory when ubldr is running, and it serves as a kind of mini-bios,
> providing access to console, disk, and network IO.
>
> I heard a rumor a while back that Patrick Kelsey had some patches for
> u-boot to fix problems with probing for disk devices.  It may be that
> they were only needed for older versions of u-boot, I'm not sure.

I do have Patrick's fixes for u-boot.  Interestingly, the same u-boot
(2013.4 + Patrick's patches) works with 11-CURRENT but not 10-STABLE
-- that's booting from eMMC, there are no issues booting from SD; also
once booted from SD, there is no issues mounting the eMMC and
accessing it (well ... aside from lock reversal warnings and the
occasional sdhc timeout).

Is there a way to debug this?

Thanks!