I’ve uploaded a new USB installation image for x86_64 for testing:

  http://www.fdn.fr/~lcourtes/software/guix/gnu-usb-install-20140718.x86_64.xz
  SHA1: ac944214af34d62b585fa089cd333c1e007be7f2
  (105 MiB)

Use alt-f2 to see the relevant doc.

Feedback welcome!

Ludo’.