The initramfs-overlay package became a trivial install with OverlayFS being accepted into the kernel a few years back. This meant the mess systemd created each

The initramfs-overlay package became a trivial install with OverlayFS being accepted into the kernel a few years back. This meant the mess systemd created each boot, could be dropped into the ram-drive with zero impact on the OS image. Effectively turning any Debian based system into a read-only OS backing image, but retaining the ability to boot into a normal writable system with a single boot flag. This trick is a lot less finicky these days. =)