Cannot boot after installation

[Erik Giorgis]

Hi!

I'm trying to install Guix on my desktop, but I'm having some behaviour that I 
can't explain. The installation proceeds without problems, I partition a new 
drive, and the installer exits successfully:

initializing operating system under '/mnt'...
copying to '/mnt'...
populating '/mnt'...
(grub gets downloaded and installed)
guix system: bootloader successfully installed on /boot/efi
Command ("guix" "system" "init" "--fallback" "/mnt/etc/config.scm" "/mnt") 
succeeded
Press Enter to continue.

However, when I reboot there is no available boot entry in Bios. 
If I look into /mnt, it seems to me like some files are missing. There is no 
proc, dev, usr directories, and /home is empty.
I tried installing 4 times, every time with slight changes (guided partitioning 
vs manual, GUI install vs CLI) but I get the same result. 

Any idea?

Best,
Erik