EFI_STAGING_SIZE - what exactly is limited and trouble with high value

[Subbsd]

Hello,

After https://lists.freebsd.org/pipermail/svn-src-stable-11/2016-September/000503.html
commits and with same reason as
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=209944 ( i have
mfs-based images more than ~512M size) , I tried to increase
EFI_STAGING_SIZE up to 1024 ( my server have 16 GB RAM ) and got  a
system hang with follow message:
--
Booting ...
Start @ 0xffffffff80301000 ...
Efi framebuffer information:
addr, size 0xe9000000, 0x500000
dimensions 1280 x 1024
stride 1280
masks 0x00ff0000 0x0000ff00, 0x000000ff, 0xff000000
---

If i reduce EFI_STAGING_SIZE to 768, system booted as usual.

Can someone explain -- what exactly is limited EFI_STAGING_SIZE in
1GB, which leads boot to freeze ? This is normal ? And why this value
can not be dependent from hw.physmem ?

We increase EFI_STAGING_SIZE by 16 Megabytes, from 48 to 64, but i'm
sure, and some may have more than 64 MB