maintainer-feedback requested: [Bug 294540] sysutils/edk2: Serial console goes bezerk after upgrade to g202508 if no fbuf (graphics) is attached

Bugzilla Automation <bugzilla@FreeBSD.org> has asked freebsd-uboot (Nobody)
<uboot@FreeBSD.org> for maintainer-feedback:
Bug 294540: sysutils/edk2: Serial console goes bezerk after upgrade to g202508
if no fbuf (graphics) is attached
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294540



--- Description ---
Upgraded host to:
FreeBSD deblndw013x.innomotics.net 14.4-STABLE FreeBSD 14.4-STABLE 818243722
GENERIC amd64

running bhyve via vm-bhyve:
# cat kinexon.conf
loader="uefi"
cpu="8"
memory="16G"
network0_type="virtio-net"
network0_switch="VL-G-DE-SP02-4181"
uuid="291fed2d-71d4-11f0-8490-b499bac04fbe"
network0_mac="58:9c:fc:09:5e:14"
bhyve_options="-K de -o system.serial_number=CZ3139VJ30KNXE"
fwcfg="qemu"

and trying to enter the UI App (UEFI window) the serial output goes bezerk. As
soon as I enable graphics it works again. I have uploaded a video of the
behavior.

Using:
# pkg info edk2*
edk2-bhyve-g202508

See video of the behavior:
https://people.freebsd.org/~michaelo/bhyve/bhyve-putty-bezerk-nofbuf.mp4