diff --git a/foreign/c/primitives/racket.scm b/foreign/c/primitives/racket.scm
index 11032ac..6589941 100644
--- a/foreign/c/primitives/racket.scm
+++ b/foreign/c/primitives/racket.scm
@@ -59,11 +59,11 @@
 
 (define c-bytevector-u8-set!
   (lambda (c-bytevector k byte)
-    (ptr-set! c-bytevector _byte k byte)))
+    (ptr-set! c-bytevector _uint8 k byte)))
 
 (define c-bytevector-u8-ref
   (lambda (c-bytevector k)
-    (ptr-ref c-bytevector _byte k)))
+    (ptr-ref c-bytevector _uint8 k)))
 
 (define c-bytevector-pointer-set!
   (lambda (c-bytevector k pointer)