marusich helped me in IRC by mentioning the date app (and hwclock).
I'm going to try and get Grub installed into my fully encrypted disk
although I haven't taken a good look at the bug which might be too
advanced: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=21843. I'm also
studying these pages:
- https://lists.gnu.org/archive/html/bug-guix/2016-03/msg00088.html
- https://www.gnu.org/software/guix/manual/guix.html#File-Systems
- https://gnunet.org/bot/log/guix/2015-09-12

Kete Foy:
> Hello, I am trying to install GuixSD, and my system time is much older
> than the present; so the system won't install. It tells me to check the
> system clock.
> 
> Unusual distinction—I chose to encrypt the system. Libreboot is supposed
> to be able to boot an encrypted system. If it makes a difference, my
> config.scm has (bootloader (grub-configuration (device
> "/dev/mapper/cryptsys"))). In the Guix manual, I noticed a section about
> encrypted systems that looked like it was meant for after the
> installation, and Libreboot has its own instructions for the initial
> boot and setting up subsequent boots: decrypting to find the kernel in
> /boot.
>