diff --git a/project.py b/project.py
index 1b0769a..65fefd9 100644
--- a/project.py
+++ b/project.py
@@ -1670,8 +1670,10 @@
     if GitCommand(self, cmd).Wait() != 0:
       raise GitError('%s rebase %s ' % (self.name, upstream))
 
-  def _FastForward(self, head):
+  def _FastForward(self, head, ffonly=False):
     cmd = ['merge', head]
+    if ffonly:
+      cmd.append("--ff-only")
     if GitCommand(self, cmd).Wait() != 0:
       raise GitError('%s merge %s ' % (self.name, head))
 
diff --git a/subcmds/download.py b/subcmds/download.py
index f79f485..0ea45c3 100644
--- a/subcmds/download.py
+++ b/subcmds/download.py
@@ -39,6 +39,9 @@
     p.add_option('-r','--revert',
                  dest='revert', action='store_true',
                  help="revert instead of checkout")
+    p.add_option('-f','--ff-only',
+                 dest='ffonly', action='store_true',
+                 help="force fast-forward merge")
 
   def _ParseChangeIds(self, args):
     if not args:
@@ -87,5 +90,7 @@
         project._CherryPick(dl.commit)
       elif opt.revert:
         project._Revert(dl.commit)
+      elif opt.ffonly:
+        project._FastForward(dl.commit, ffonly=True)
       else:
         project._Checkout(dl.commit)