diff --git a/bin/egencache b/bin/egencache
index 3859a06..54c517e 100755
--- a/bin/egencache
+++ b/bin/egencache
@@ -860,7 +860,7 @@
 
 	if options.repositories_configuration is not None:
 		env['PORTAGE_REPOSITORIES'] = options.repositories_configuration
-	elif options.portdir_overlay:
+	elif options.portdir_overlay is not None:
 		env['PORTDIR_OVERLAY'] = options.portdir_overlay
 
 	if options.cache_dir is not None:
diff --git a/pym/portage/_emirrordist/main.py b/pym/portage/_emirrordist/main.py
index 3c7b81a..f28aad7 100644
--- a/pym/portage/_emirrordist/main.py
+++ b/pym/portage/_emirrordist/main.py
@@ -253,7 +253,7 @@
 
 	if options.repositories_configuration is not None:
 		env['PORTAGE_REPOSITORIES'] = options.repositories_configuration
-	elif options.portdir_overlay:
+	elif options.portdir_overlay is not None:
 		env['PORTDIR_OVERLAY'] = options.portdir_overlay
 
 	if options.portdir is not None: