diff --git a/support/chez/support.ss b/support/chez/support.ss
index a1d3b8f33..79a069874 100644
--- a/support/chez/support.ss
+++ b/support/chez/support.ss
@@ -1,6 +1,9 @@
 (define (blodwen-os)
   (case (machine-type)
-    [(i3le ti3le a6le ta6le) "unix"]
+    [(i3le ti3le a6le ta6le) "unix"]  ; GNU/Linux
+    [(i3ob ti3ob a6ob ta6ob) "unix"]  ; OpenBSD
+    [(i3fb ti3fb a6fb ta6fb) "unix"]  ; FreeBSD
+    [(i3nb ti3nb a6nb ta6nb) "unix"]  ; NetBSD
     [(i3osx ti3osx a6osx ta6osx) "darwin"]
     [(i3nt ti3nt a6nt ta6nt) "windows"]
     [else "unknown"]))