diff --git a/live-build/isobuilder/builder.py b/live-build/isobuilder/builder.py
index 98e37ed7..8ca6522a 100644
--- a/live-build/isobuilder/builder.py
+++ b/live-build/isobuilder/builder.py
@@ -366,7 +366,7 @@ class ISOBuilder:
             if volid:
                 cmd.extend(["-volid", volid])
             cmd.extend(mkisofs_opts)
-            cmd.extend(["-map", self.iso_root])
+            cmd.extend(["-map", self.iso_root, "/"])
         else:
             # xorriso with "-as mkisofs" runs in mkisofs compatibility mode on
             # other architectures.  -r enables Rock Ridge extensions for Unix