i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom E3940)

[Andre Albsmeier]

I have a lot of machines running with 4 GB physical RAM and, for
some reasons, I still have to use a 32 bits OS.

All of them show something between 3 and 3.5 GB of RAM available
in dmesg but the brand new Supermicro A2SAV really shocked me:

FreeBSD 11.1-STABLE #0: Mon Jan 15 06:57:10 CET 2018
...
real memory  = 4294967296 (4096 MB)
avail memory = 1939558400 (1849 MB)
...

So do people have any ideas how I might get a bit closer to at least
3 GB? I assume there are no FreeBSD knobs which might help but hope
dies last...