Booting my Opensuse Leap 15.1 fails sometimes and the booting is stuck. Most often a message "Failed to start LVM2 PV scan on device 8:34" is displayed, but sometimes the boot fails on remounting the root device, and sometimes for other reasons as well (albeit I have an impression that it's still storage-related).
After the failure, a hard reset sometimes helps - and then the system boots and works perfectly normal - but sometimes it fails again for this same or for another reason.
Now: is there a way to start an emergency shell right away from such a stuck boot to make some diags before they are erased by the next boot? I tried to google it, but all I've found were advices how to modify the kernel command line parameters in grub or how to switch to an emergency mode on a running system. It's not what I'm looking for, because by that time the grub is long gone, and there's no shell available yet to enter 'systemctl' command. So I guess that at this stage it would probably have to be something sensing a magic key combination of some sort.
A note for purists: if such a method exists, then what it is? ;-)
Thank you very much upfront.