In case it could be useful for you to experiment, there are Devuan netboost installer images for "orangepi_zero_plus2" and for various other ARM models (i.e. a64-olinuxino, firefly-rk3399,nanopi_neo2, pine64_plus, pinebook-pro, pinebook puma-rk3399, rock-pi-4, rock64, rockpro64, teres_i) that would require to be concatinated with its 'model-specific' firmware.  You may know of that image already and may have passed on it as it is not for your model exactly (I don't know how much it could help - I've not tried it), but if it can help anyone I am flagging those images up by name in this post and, for guidance, there is also README page there.

(Of course, there are also ready images for the Orange Pi One Plus, the Rock Pi, Raspberry Pi, etc at the usual community-build ARM images download page.)

I guess Pi zero 3 is different from Pi-3G, but once they arrive I'll follow your instructions to setup them.

Oh, W1 over GPIO doesn't work. There is no DTO for that. I would be very thankful if somebody explained how to make it working.

Never mind, I've managed to write it myself. Now my thermometers work
The overlay and a short description is on Blogspot. Use Da Googl for a translation.

• Installed a Debian image from the device's page and booted it once to check if it works and let it resize its root FS. It is necessary.

• Got a modified debootstrap from https://git.devuan.org/devuan/debootstrap

• Debootstrapped with ./debootstrap --foreign --arch=armhf daedalus dev1 http://192.168.1.254:9999/devuan daedalus into "dev1" directory (http://192.168.1.254:9999/devuan is my local apt-cache service address)

• Installed qemu-user-static and copied /usr/bin/qemu-arm-static into dev1/usr/bin/qemu-arm-static

• Chrooted with an emulation using chroot dev1 /usr/bin/qemu-arm-static /bin/bash

• In the chroot executed export DEBOOTSTRAP_DIR=/debootstrap; /debootstrap/debootstrap --second-stage

Voila (well, kind of). We should now copy contents our "dev1" directory to our SD card with Debian installed. Please note that in my scheme we should preserve /boot, /lib/modules (/usr/lib/modules) and /lib/firmware (/usr/lib/firmware) directories from the original Debian installation. Note that /lib/firmware and /lib/modules are symlinks; they should become real directories in Devuan.

So that's it. Just change first getty line in /etc/inittab to "1:2345:respawn:/sbin/agetty --noclear -8 ttyS0 115200,38400,9600 linux" and comment out all the others gettys. Boot the Pi, connect with a console cable and configure your fresh system.

Oh, W1 over GPIO doesn't work. There is no DTO for that. I would be very thankful if somebody explained how to make it working.
"reboot" command loses both wired and wireless network interfaces until a power cycle.

I've just got an Orange Pi Zero 3.

Please show me a way to get/make Devuan install image for it (it is based on Allwinner-H618 which is Cortex A53).

In short: is there a documentation which more or less clearly defines a way to port Devuan to a hardware similar to that it already supports?

Thank you.