diff --git a/src/bootfiles/21c/boot-21c-cross-x86.lisp b/src/bootfiles/21c/boot-21c-cross-x86.lisp
index 7ac6cc7fddc8c28ec184fba10c2ac885f26c0403..a42956e1bff0021e68a63a02115c2dc2c17e2448 100644
--- a/src/bootfiles/21c/boot-21c-cross-x86.lisp
+++ b/src/bootfiles/21c/boot-21c-cross-x86.lisp
@@ -20,7 +20,7 @@
      :gencgc				; Generational GC
      :conservative-float-type
      :hash-new
-     :random-xoroshiro
+     :random-xoroshiro			; xoroshiro128+ RNG
      :cmu :cmu20 :cmu20a		; Version features
      :double-double			; double-double float support
      )