UEFI ISO boot not working in 12.1 ?

[Chris Ross]

On Wed, Nov 06, 2019 at 02:17:11PM -0500, Chris Ross wrote:
> 
> Hi there.  I tried booting FreeBSD-12.1-RELEASE-amd64-disc1.iso on a system
> here, which didn't work, and I found that FreeBSD-12.0-RELEASE-amd64-disc1.iso
> did work on that same system.  [Systems were configured to boot in UEFI mode]
> 
> And continues on from there.   However, the attempt to boot 12.1-RELEASE
> never loads the loader and allows it to boot.  The console output
> for 12.1-RELEASE is below.  Can anyone help me figure out if it's something
> I need to do?  How has 12.1 changed w.r.t. 12.0 for UEFI?

More information.  A stable/12 ISO that I built fails in the same way the
12.1-RELEASE ISO did.  But, I just grabbed releng/12.0, and built a release
ISO, and it boots.  So, something seems definately to have changed in the way
the UEFI bits are on the boot ISOs?  Or maybe a change in the loader?  
Is okay in releng/12.0, but broken in 12.1-RELEASE and stable/12.

Let me know what to try next.

            - Chris