bug#27064: after GuixSD installation

[Quiliro]

After installation (with no error mesage), I reboot. These is the output of:
guix system init /mnt/etc/bare-bone.scm /mnt --fallback
http://sprunge.us/SXgC
GrUB starts to boot the system. Then the message
waiting for "my-root" partition
appears. Finally a Guile prompt appears after the following messages:
Error: in proceedure scm-error
failed to resolve partition "my-root"
I have tryed this 8 times changing different things such as label for uefi in 
bare-bones.scm:
http://sprunge.us/AhcN
http://sprunge.us/ZFAG