diff --git a/panda/src/downloader/Sources.pp b/panda/src/downloader/Sources.pp
index 6c8e7f644e..1e92656e6f 100644
--- a/panda/src/downloader/Sources.pp
+++ b/panda/src/downloader/Sources.pp
@@ -81,7 +81,7 @@
     httpEnum.h \
     identityStream.I identityStream.h identityStreamBuf.h \
     multiplexStream.I multiplexStream.h \
-    multiplexStreamBuf.I multiplexStreamBuf.I \
+    multiplexStreamBuf.I multiplexStreamBuf.h \
     patcher.h patcher.I \
     socketStream.h socketStream.I \
     urlSpec.h urlSpec.I