Hi all.   I wrote a small guide on enabling pps-gpio by modifying the device tree. With a PPS signal it's possible to setup your board as a Stratum 1 time server for your local network or the NTP pool. I used this method on a Rock64 but it should be applicable on most board.   PPS-GPIO on Rock64 with Armbian legacy (4.4.X) kernel   Cheers.