diff --git a/b9.cabal b/b9.cabal
--- a/b9.cabal
+++ b/b9.cabal
@@ -1,5 +1,5 @@
 name:                b9
-version:             0.5.60
+version:             0.5.61
 
 synopsis:            A tool and library for building virtual machine images.
 
diff --git a/src/cli/Main.hs b/src/cli/Main.hs
--- a/src/cli/Main.hs
+++ b/src/cli/Main.hs
@@ -39,6 +39,8 @@
                 &  customB9Config
                 %~ (over envVars (++ vars) . const (overrides ^. customB9Config)
                    )
+                &  customLibVirtNetwork
+                .~ (overrides ^. customLibVirtNetwork)
                 &  maybe id
                          overrideB9ConfigPath
                          (overrides ^. customB9ConfigPath)
@@ -180,8 +182,8 @@
                   , _customB9Config       = b9cfg
                   , _customLibVirtNetwork =
                       (\n -> if n == hostNetworkMagicValue
-                              then Just n
-                              else Nothing
+                              then Nothing
+                              else Just n
                           )
                           <$> libvirtNet
                   }
@@ -207,7 +209,7 @@
                    (strArgument idm)
                )
                (progDesc
-                   "Run a command on the lastest version of the specified shared image. All modifications are lost on exit."
+                   "Run a command on the lastest version of the specified shared image."
                )
            )
     <> command
diff --git a/src/lib/B9/B9Config.hs b/src/lib/B9/B9Config.hs
--- a/src/lib/B9/B9Config.hs
+++ b/src/lib/B9/B9Config.hs
@@ -247,8 +247,13 @@
             let rc = permanentConfig Sem.<> (cfg ^. customB9Config)
             in  case cfg ^. customLibVirtNetwork of
                   Just overridenNetwork ->
-                    rc & libVirtLXCConfigs . _Just . networkId .~ overridenNetwork
+                    rc
+                      &  libVirtLXCConfigs
+                      .  _Just
+                      .  networkId
+                      .~ overridenNetwork
                   Nothing -> rc
+
       (res, permanentB9ConfigUpdates) <- runWriterT
         (runReaderT (runB9ConfigAction act) runtimeCfg)