diff --git a/common-main.c b/common-main.c
index 0a22861f1..4653d18b5 100644
--- a/common-main.c
+++ b/common-main.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "exec-cmd.h"
 #include "attr.h"
+#include <montauk-init.h>
 
 /*
  * Many parts of Git have subprograms communicate via pipe, expect the
@@ -28,6 +29,13 @@ int main(int argc, const char **argv)
 	int result;
 	struct strbuf tmp = STRBUF_INIT;
 
+	/*
+	 * MontaukOS: fill in what the process environment cannot carry
+	 * (HOME). Must run before any config is read. See
+	 * compat/montauk-compat.c in the port.
+	 */
+	montauk_startup();
+
 	trace2_initialize_clock();
 
 	/*