diff --git a/ml-proto/src/spec/memory.ml b/ml-proto/src/spec/memory.ml
index 7f337fccd6..93afc3dc44 100644
--- a/ml-proto/src/spec/memory.ml
+++ b/ml-proto/src/spec/memory.ml
@@ -92,7 +92,8 @@ let load64 mem a =
   Int64.logor (Int64.of_int32 (load32 mem a)) (Int64.shift_left (Int64.of_int32 (load32 mem (a+4))) 32)
 
 let store8 mem a bits =
-  !mem.{a} <- Int32.to_int (Int32.logand bits (Int32.of_int 255))
+  (* Store the lowest 8 bits of "bits" at byte index a, discarding the rest. *)
+  !mem.{a} <- Int32.to_int bits
 
 let store16 mem a bits =
   store8 mem (a+0) bits;