What I would like to do is put together my own 64 bit Raspbian/Debian disk image, using the RPi kernel built for 64 bit (so that it will still use the Raspbian dt overlays) and with a matching 64 bit Debian minimal install.
The reason for wanting to do this is so I can still access the pps-gpio.dtbo in order to use a GPS with PPS for an NTP time server. I've tried Debian, OpenSuse, Archlinux and FreeBSD 12 arm64 distros and none will, that I can tell, use any of the Raspbian dt overlays, which makes specifying a PPS pin over GPIO all but impossible.
The kernel I can build and boot easily. Where I'm struggling is moving from the Raspbian arm6 binaries to aarch64 binaries (the rootfs). Can anyone point me to a guide (I have googled, promise), or offer any help in doing this? Thanks in advance.