custom install and missing kenv defaults

Hello,

I'm using custom install script for setting up FreeBSD on large disks 
(you know, that 10-years-ago-and-still-there issue with "cannnot read 
MOS, all block copies unavailable" when book blocks migrate over 2TB), 
but I was using it only on legacy gptzfsboot servers, Nowadays I 
converted it to UEFI, and now I can see that this installation cannot 
boot atomatically, because it searches for the kernel in /boot. I know 
about loader.conf, for sure, but servers installed with bsdinstall don't 
have kernel_path set there (along with module_path), yet it works fine. 
I've also checked the kernel for the bundled env variables - none.

So, my question is - where are the kernel_path and module path set when 
the bsdinstall does the installation ?

Thanks.