Hello,
I am using lubuntu 14.04 and I installed the binary version of guix 
following the documentation ( 
https://www.gnu.org/software/guix/manual/html_node/Binary-Installation.html#Binary-Installation 
)

Then I ran `guix pull`, made a new partition (ext4) and tried to run 
`guix system init` on it:

$ sudo guix system init /mnt/etc/config.scm /mnt

The config.scm is attached. The interesting part is that I specified to 
install grub on /dev/sda9 ( the root partition for guix) instead of 
/dev/sda. The command failed saying that "Embedding is not possible" ( 
here details: https://paste.debian.net/282642/ ).

Following the advice got from Mark on the IRC channel I tried specifing 
the --no-grub flag, but got an other error:

tyrion ~$ sudo guix system init --no-grub /mnt/etc/config.scm /mnt
[sudo] password for tyrion:
warning: failed to install locale: Invalid argument
/gnu/store/q32xg8nmyjwrl5yc18hj7ay5h4rgzkgy-system

initializing operating system under '/mnt'...
guix system: error: build failed: path 
`/gnu/store/hill6gywff6p2c3h1zbc7h5xj0cr4yn2-grub.cfg' is not valid

I also trying reinstalling guix by deleting /gnu, /var/guix, and 
/var/log/guix (and also wiping the partition with rm)
and following again the documentation. Tried again the last command and 
got the same error again.