Comment # 25 on bug 1224773 from Stefan Dirsch

Thanks for figuring this out, Imo! So it seems 

  transactional-update initrd

doesn't work in a consistent way, at least not together with systemd-boot.
Ignaz will look into this.

I'm wondering if we're seing two separate issues here. Could you check once
more by re-installing the KMP if transactional-update initrd is being running
during that installation (it should!)? I need to know if the initrd is just
being installed to the wrong location or systemd-boot configuration not
adjusted correctly respectively. Or if no initrd is being re-created at all
during KMP installation.