The handbook mentions that a FreeBSD installation requires a minimum 64 MB of RAM. Upon on testing, I discovered that on 9.3 & 10.3 (both amd64 builds) whilst the kernel boots & installer runs with such an amount, the installer fails when attempting to extract a set.
On 11-BETA1 it's not actually possible to boot the kernel with less than 96MB (amd64) or 92MB (i386).
Attached patch increases the minimum RAM requirement for installation to 96MB