diff --git a/hosts/ocaml/lib/sx_ref.ml b/hosts/ocaml/lib/sx_ref.ml
index ece7a0cd..de0d86d5 100644
--- a/hosts/ocaml/lib/sx_ref.ml
+++ b/hosts/ocaml/lib/sx_ref.ml
@@ -111,7 +111,7 @@ and make_case_frame match_val remaining env =
 
 (* make-thread-frame *)
 and make_thread_frame remaining env mode name =
-  (CekFrame { cf_type = "thread"; cf_env = env; cf_name = name; cf_body = Nil; cf_remaining = remaining; cf_f = Nil; cf_args = Nil; cf_results = Nil; cf_extra = Nil; cf_extra2 = Nil })
+  (CekFrame { cf_type = "thread"; cf_env = env; cf_name = name; cf_body = Nil; cf_remaining = remaining; cf_f = Nil; cf_args = Nil; cf_results = Nil; cf_extra = mode; cf_extra2 = Nil })
 
 (* thread-insert-arg *)
 and thread_insert_arg form value fenv =
diff --git a/hosts/ocaml/transpiler.sx b/hosts/ocaml/transpiler.sx
index 1d18e69d..f8b083c2 100644
--- a/hosts/ocaml/transpiler.sx
+++ b/hosts/ocaml/transpiler.sx
@@ -562,6 +562,8 @@
                 (ef "update-fn")
                 (some (fn (k) (= k "head-name")) items)
                 (ef "head-name")
+                (some (fn (k) (= k "extra")) items)
+                (ef "extra")
                 :else "Nil")
               "; cf_extra2 = "
               (cond
@@ -1843,16 +1845,20 @@
                   (if
                     (and (number? nl-idx) (>= nl-idx 0))
                     (let
-                      ((before (slice p 0 (+ nl-idx 1)))
+                      ((before (slice p 0 nl-idx))
                         (after (slice p (+ nl-idx 1))))
-                      (if
+                      (cond
                         (starts-with? after "let rec ")
-                        (str before "and " (slice after 8))
-                        p))
-                    (if
+                        (str before "\nand " (slice after 8))
+                        (starts-with? after "let ")
+                        (str before "\nand " (slice after 4))
+                        :else p))
+                    (cond
                       (starts-with? p "let rec ")
                       (str "and " (slice p 8))
-                      p))))
+                      (starts-with? p "let ")
+                      (str "and " (slice p 4))
+                      :else p))))
               (rest parts))))))))
 
 (define