As far as I remember you have to configure something.
Give me a minute please.
Here [Tip] Enable Magic SysRq Key (REISUB)
I hope this helps.
Let me know how it goes with you.
Just to update you:
- I converted to
dracut
Install dracut? - And converted to systemd-boot Convert to systemd-boot with dracut?
I am on BTRFS by the way.
I noticed much faster boot time with dracut + systemd-boot.