diff --git a/ecp5/archdefs.h b/ecp5/archdefs.h
index c4d25a50..84a431fd 100644
--- a/ecp5/archdefs.h
+++ b/ecp5/archdefs.h
@@ -22,7 +22,7 @@
 #error Include "archdefs.h" via "nextpnr.h" only.
 #endif
 
-#include <boost/functional/hash_fwd.hpp>
+#include <boost/functional/hash.hpp>
 
 NEXTPNR_NAMESPACE_BEGIN
 
diff --git a/ice40/archdefs.h b/ice40/archdefs.h
index 3252dabf..2bb718f1 100644
--- a/ice40/archdefs.h
+++ b/ice40/archdefs.h
@@ -21,7 +21,7 @@
 #error Include "archdefs.h" via "nextpnr.h" only.
 #endif
 
-#include <boost/functional/hash_fwd.hpp>
+#include <boost/functional/hash.hpp>
 
 NEXTPNR_NAMESPACE_BEGIN