diff --git a/tools/buildzip.pl b/tools/buildzip.pl
index b44ed91e8e..b9c9366e6c 100755
--- a/tools/buildzip.pl
+++ b/tools/buildzip.pl
@@ -47,7 +47,7 @@ sub buildzip {
     mkdir ".rockbox", 0777;
     mkdir ".rockbox/langs", 0777;
     mkdir ".rockbox/rocks", 0777;
-    `find . -name "*.rock" ! -empty | xargs --replace=foo cp foo .rockbox/rocks/`;
+    `find . -name "*.rock" -o -name "*.ovl" ! -empty | xargs --replace=foo cp foo .rockbox/rocks/`;
 
     open VIEWERS, "$ROOT/apps/plugins/viewers.config" or
         die "can't open viewers.config";
@@ -63,6 +63,11 @@ sub buildzip {
                 `mv .rockbox/rocks/$1 .rockbox/viewers`;
                 print VIEWERS $_;
             }
+            elsif(-e ".rockbox/viewers/$1") {
+                # in case the same plugin works for multiple extensions, it
+                # was already moved to the viewers dir
+                print VIEWERS $_;
+            }
         }
     }
     close VIEWERS;