Build OPNsense 25.1.3 nano image from source

1. System Requirements:

For OPNsense 25.1.3, we need FreeBSD 14.2.

2. Install Required Dependencies:

pkg install git

3. Grab the repositories:

cd /usr
git clone https://github.com/opnsense/tools
cd tools
make update VERSION=25.1.3

4. Build:

make nano VERSION=25.1.3

If you have following error,

Just run the command it prompted, and build again, if successful, a nano image can be found under:

make print-IMAGESDIR