Brief Summary:
It appears as though the Guix installer does not reformat the EFI/ESP partition if it already exists.

Step to reproduce this bug:
With a computer which already has an ESP partition, go through the graphical installation and do not reformat/delete/modify the existing EFI/ESP partition. When you confirm the partitioning changes, you may notice that the EFI partition remains unmodified.

Effects:
It creates a GRUB2 error which states that it can not find the filesystem properly. In my case, it’s because Grub expected a previous OS’s filesystem information (Fedora), but as the EFI partition was not modified in the install, the .cfg did not reflect the new GUIX filesystem UUID.

What do you think should happen:
When installing using the guided installer, have the GUIX installer automatically modify/reformat the ESP/EFI partition. This ensures that that GRUB2 can find the new GUIX UUID upon reboot.

Hardware:
Lenovo X1 Carbon

Kernel:
Linux-Libre Kernel

ISO:
Latest Snapshot Iso

Thank you for your time, please let me know if additional information is needed.