diff --git a/guix/channels.scm b/guix/channels.scm
index 476d62e1f4..a5283b4bf4 100644
--- a/guix/channels.scm
+++ b/guix/channels.scm
@@ -122,7 +122,7 @@
   channel?
   (name      channel-name)
   (url       channel-url)
-  (branch    channel-branch (default "master"))
+  (branch    channel-branch (default #f))
   (commit    channel-commit (default #f))
   (introduction channel-introduction (default #f))
   (location  channel-location
@@ -179,7 +179,6 @@ to the corresponding bytevector."
 (define %default-guix-channel
   (channel
    (name 'guix)
-   (branch "master")
    (url %default-channel-url)
    (introduction %guix-channel-introduction)))
 
@@ -225,7 +224,9 @@ introduction, add it."
   "Return the \"reference\" for CHANNEL, an sexp suitable for
 'latest-repository-commit'."
   (match (channel-commit channel)
-    (#f      `(branch . ,(channel-branch channel)))
+    (#f      (if (channel-branch channel)
+                 `(branch . ,(channel-branch channel))
+                 '()))                            ;remote HEAD
     (commit  `(commit . ,(channel-commit channel)))))
 
 (define sexp->channel-introduction
diff --git a/guix/inferior.scm b/guix/inferior.scm
index 7c8e478f2a..3db63167fd 100644
--- a/guix/inferior.scm
+++ b/guix/inferior.scm
@@ -732,7 +732,10 @@ prefix, resolve it; and if 'commit' is unset, fetch CHANNEL's branch tip."
         (branch (channel-branch channel)))
     (if (and commit (= (string-length commit) 40))
         commit
-        (let* ((ref (if commit `(commit . ,commit) `(branch . ,branch)))
+        (let* ((ref (cond
+                     (commit `(commit . ,commit))
+                     (branch `(branch . ,branch))
+                     (else   '())))               ;remote HEAD
                (cache commit relation
                      (update-cached-checkout (channel-url channel)
                                              #:ref ref