Hello,
Not sure too if still relevant. But, I've experience myself this message "Screen will stop updating, please got to find.synology.com" WITH NOTHING MORE HAPPENED. In my environment, the reason was the disk type. KVM seems always set it by default to IDE. I just had to change it to SATA. And then, the installation run fine. As mentioned in other post threads, if you use KVM, the disk type must NOT be USB but SATA (or eventually IDE if you are still using IDE disk). I didn't have to modify something else, no need in my environment to set/modify loader parameters.