Welcome to Grub!... for a minute

[Yasuaki Kudo]

Hi,

I just wanted to report (although this is probably already known) that I had to 
wait for a long time (probably more than a minute) staring at "Welcome to 
Grub!" screen upon reboot, after accumulating thousands of guix system 
generations.  I was experimenting with something and I suspected that was the 
cause - sure enough, after deleting them all with guix system 
delete-generations command, the delay disappeared.

Just reporting 😄