NanoPI Neo freezes on boot when changing init system to sysV on armbian squeeze

I'm using a NanoPI NEO (v1.31 Lite, 512M RAM) which has an Allwinner H3 cpu; running Armbian Stretch from here:

https://www.armbian.com/nanopi-neo/

When changing the init system from the default systemd to sysV init as described at

http://without-systemd.org/wiki/index.php/How_to_remove_systemd_from_a_Debian_Stretch_installation

on the next boot, the boot process freezes.

Installing the package sysvinit-core conflicts with systemd-sysv, depending on which resolution I choose (install systemd-shim and some libraries, or remove systemd-sysv and NetworkManager), the boot process freezes at one of the following 3 lines:

[....] Starting OpenBSD Secure Shell server: sshd. ok
[....] Setting sysfs variables.... ok
[....] Starting network connection manager: NetworkManager. ok

As this is after the bootloader, the initramfs, the kernel and the init process, I'm not sure on how to fix this.

I tried the process of flashing, apt update/upgrade and install sysvinit-core several times, the freezes are always there.

Any ideas on what to try, how to avoid the freezes or how to fix this?