When trying to run sysutils/vbetools (installed via pkg) with any arguments I see
"mmap /dev/mem: Invalid argument"
"Failed to initialize LRMI (Linux Real-Mode Interface)".
Output of truss:
So my guess is that the combination of hint address 0 and MAP_FIXED does not work.
Tested FreeBSD versions are 9.1, 10.2 and 10.3.
Same with Freebsd 11.2/amd64