Linux kernel Source for FortiAP 321-C

Good day.

I have received a FortiNet FortiAP 321-C that was decomissioned two years ago, and I want to get the source code used to compile a kernel, for personal use.

This gateway will not be used in any commercial setting, only for experimentation and personal use of the hardware.

Is this sharing of source code possible, and sources to u-boot as well?

TIA