I was playing around with some boot codes and my private update-grub command and on reboot found an init line
which comes from /etc/default/grub
It had a "default" entry which I failed to spot initially that read
# GRUB_CMDLINE_LINUX_DEFAULT="quiet verbose=no"
# Replace command below /sbin/init with
# /sbin/runit-init for runyx init
# /sbin/systemd-init for systemd init
GRUB_CMDLINE_LINUX="init=/sbin/init"
"
EDIT fix up line as I have checked the base config. And had not backed up before changing
1) I believe we have
/sbin/run-init
/sbin/systemd-init
2) but I can NOT boot with a menu entry stanza of "/sbin/run-init"
ignoring the fact that I installed into a spare partition my menu that boots for me reads
linux /boot/kernel-stable root=/dev/sda3 ro quiet <and some other stuff>
thanks for reading