How To Build From Source For Different Architecture

[ensal]

I've recently got my hands on a Juniper SRX210 for free and seeing that it uses linux uboot to then boot into freebsd I wanted to see if it would be possible to get a build of OPNsense that would work on this. I'd love to get my OPNsense off of my server and back on to it's own hardware so it's more convenient on the family if I work on the server and take it down I don't take the internet with it. The cpu is mips based it's one of the Octeon family processors but I don't remember the exact one. I know that OPNsense has mips technically built in through freebsd but is only built for x86. I've got basically no experience with doing a build from source so I want to see if anybody else may have some experience that could assist with this crazy project of mine. My goal is to get a bootable serial installer for mips architecture. I've setup a freebsd VM that would be my build machine and have added mips into the build.conf file but it fails since I know there are several additional edits that would be needed to do this. If anybody has some time or wants to throw some pointers my way I would greatly appreciate it.