diff -r 928732ec00dd -r fa44db7da2dc migration.py
--- a/migration.py	Thu Jul 17 11:08:56 2014 +0200
+++ b/migration.py	Fri Jul 18 17:35:25 2014 +0200
@@ -414,7 +414,9 @@
             toremove = (cube,)
         origcubes = self.config._cubes
         basecubes = [c for c in origcubes if not c in toremove]
-        self.config._cubes = tuple(self.config.expand_cubes(basecubes))
+        # don't fake-add any new ones, or we won't be able to really-add them later
+        self.config._cubes = tuple(cube for cube in self.config.expand_cubes(basecubes)
+                                   if cube in origcubes)
         removed = [p for p in origcubes if not p in self.config._cubes]
         if not cube in removed and cube in origcubes:
             raise ConfigurationError("can't remove cube %s, "