diff --git a/src/ikarus.boot b/src/ikarus.boot
index 7a94e00..52d1d13 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.bytevectors.ss b/src/ikarus.bytevectors.ss
index 04ccd60..05c8952 100644
--- a/src/ikarus.bytevectors.ss
+++ b/src/ikarus.bytevectors.ss
@@ -5,6 +5,8 @@
           bytevector-copy! u8-list->bytevector bytevector->u8-list
           bytevector-u16-native-ref bytevector-u16-native-set!
           bytevector-u16-ref bytevector-u16-set!
+          bytevector-u32-ref bytevector-u32-set!
+          bytevector-s32-ref bytevector-s32-set!
           bytevector-s16-native-ref bytevector-s16-native-set!
           bytevector-s16-ref bytevector-s16-set!
           bytevector-fill! bytevector-copy bytevector=?
@@ -20,6 +22,8 @@
         bytevector-copy! u8-list->bytevector bytevector->u8-list
         bytevector-u16-native-ref bytevector-u16-native-set!
         bytevector-u16-ref bytevector-u16-set!
+        bytevector-u32-ref bytevector-u32-set!
+        bytevector-s32-ref bytevector-s32-set!
         bytevector-s16-native-ref bytevector-s16-native-set!
         bytevector-s16-ref bytevector-s16-set!
         bytevector-fill! bytevector-copy bytevector=?
@@ -228,14 +232,14 @@
                    ($fx< i ($fx- ($bytevector-length x) 3)))
               (case end
                 [(big) 
-                 (+ (* ($bytevector-u8-ref x i) #x1000000)
+                 (+ (sll ($bytevector-u8-ref x i) 24)
                     ($fxlogor
                       ($fxsll ($bytevector-u8-ref x ($fx+ i 1)) 16)
                       ($fxlogor 
                         ($fxsll ($bytevector-u8-ref x ($fx+ i 2)) 8)
                         ($bytevector-u8-ref x ($fx+ i 3)))))]
                 [(little) 
-                 (+ (* ($bytevector-u8-ref x ($fx+ i 3)) #x1000000)
+                 (+ (sll ($bytevector-u8-ref x ($fx+ i 3)) 24)
                     ($fxlogor
                       ($fxsll ($bytevector-u8-ref x ($fx+ i 2)) 16)
                       ($fxlogor
@@ -245,6 +249,32 @@
               (error 'bytevector-u32-ref "invalid index ~s" i))
           (error 'bytevector-u32-ref "~s is not a bytevector" x))))
 
+
+  (define bytevector-s32-ref
+    (lambda (x i end) 
+      (if (bytevector? x) 
+          (if (and (fixnum? i)
+                   ($fx<= 0 i)
+                   ($fx< i ($fx- ($bytevector-length x) 3)))
+              (case end
+                [(big) 
+                 (+ (sll ($bytevector-s8-ref x i) 24)
+                    ($fxlogor
+                      ($fxsll ($bytevector-u8-ref x ($fx+ i 1)) 16)
+                      ($fxlogor 
+                        ($fxsll ($bytevector-u8-ref x ($fx+ i 2)) 8)
+                        ($bytevector-u8-ref x ($fx+ i 3)))))]
+                [(little) 
+                 (+ (sll ($bytevector-s8-ref x ($fx+ i 3)) 24)
+                    ($fxlogor
+                      ($fxsll ($bytevector-u8-ref x ($fx+ i 2)) 16)
+                      ($fxlogor
+                        ($fxsll ($bytevector-u8-ref x ($fx+ i 1)) 8)
+                        ($bytevector-u8-ref x i))))]
+                [else (error 'bytevector-s32-ref "invalid endianness ~s" end)])
+              (error 'bytevector-s32-ref "invalid index ~s" i))
+          (error 'bytevector-s32-ref "~s is not a bytevector" x))))
+
   (define bytevector-u16-set!
     (lambda (x i n end) 
       (if (bytevector? x) 
@@ -269,25 +299,66 @@
 
   (define bytevector-u32-set!
     (lambda (x i n end) 
-      (error 'bytevector-u32-set! "not yet")
       (if (bytevector? x) 
-          (if (and (fixnum? n) 
-                   ($fx<= 0 n) 
-                   ($fx<= n #xFFFFFFFF))
+          (if (if (fixnum? n)
+                  ($fx>= n 0)
+                  (if (bignum? n)
+                      (<= 0 n #xFFFFFFFF)
+                      #f))
               (if (and (fixnum? i)
                        ($fx<= 0 i)
                        ($fx< i ($fx- ($bytevector-length x) 3)))
                   (case end
                     [(big) 
-                     ($bytevector-set! x i ($fxsra n 8))
-                     ($bytevector-set! x ($fxadd1 i) n)]
+                     (let ([b (sra n 16)])
+                       ($bytevector-set! x i ($fxsra b 8))
+                       ($bytevector-set! x ($fx+ i 1) b))
+                     (let ([b (logand n #xFFFF)])
+                       ($bytevector-set! x ($fx+ i 2) ($fxsra b 8))
+                       ($bytevector-set! x ($fx+ i 3) b))]
                     [(little) 
-                     ($bytevector-set! x i n)
-                     ($bytevector-set! x ($fxadd1 i) (fxsra n 8))]
-                    [else (error 'bytevector-u16-ref "invalid endianness ~s" end)])
-                  (error 'bytevector-u16-set! "invalid index ~s" i))
-              (error 'bytevector-u16-set! "invalid value ~s" n))
-          (error 'bytevector-u16-set! "~s is not a bytevector" x))))
+                     (let ([b (sra n 16)])
+                       ($bytevector-set! x ($fx+ i 3) ($fxsra b 8))
+                       ($bytevector-set! x ($fx+ i 2) b))
+                     (let ([b (logand n #xFFFF)])
+                       ($bytevector-set! x ($fx+ i 1) ($fxsra b 8))
+                       ($bytevector-set! x i b))]
+                    [else (error 'bytevector-u32-ref "invalid endianness ~s" end)])
+                  (error 'bytevector-u32-set! "invalid index ~s" i))
+              (error 'bytevector-u32-set! "invalid value ~s" n))
+          (error 'bytevector-u32-set! "~s is not a bytevector" x))))
+
+
+  (define bytevector-s32-set!
+    (lambda (x i n end) 
+      (if (bytevector? x) 
+          (if (if (fixnum? n)
+                  #t
+                  (if (bignum? n)
+                      (<= #x-80000000 n #x7FFFFFFF)
+                      #f))
+              (if (and (fixnum? i)
+                       ($fx<= 0 i)
+                       ($fx< i ($fx- ($bytevector-length x) 3)))
+                  (case end
+                    [(big) 
+                     (let ([b (sra n 16)])
+                       ($bytevector-set! x i ($fxsra b 8))
+                       ($bytevector-set! x ($fx+ i 1) b))
+                     (let ([b (logand n #xFFFF)])
+                       ($bytevector-set! x ($fx+ i 2) ($fxsra b 8))
+                       ($bytevector-set! x ($fx+ i 3) b))]
+                    [(little) 
+                     (let ([b (sra n 16)])
+                       ($bytevector-set! x ($fx+ i 3) ($fxsra b 8))
+                       ($bytevector-set! x ($fx+ i 2) b))
+                     (let ([b (logand n #xFFFF)])
+                       ($bytevector-set! x ($fx+ i 1) ($fxsra b 8))
+                       ($bytevector-set! x i b))]
+                    [else (error 'bytevector-s32-ref "invalid endianness ~s" end)])
+                  (error 'bytevector-s32-set! "invalid index ~s" i))
+              (error 'bytevector-s32-set! "invalid value ~s" n))
+          (error 'bytevector-s32-set! "~s is not a bytevector" x))))
 
   (define bytevector-s16-ref
     (lambda (x i end) 
diff --git a/src/makefile.ss b/src/makefile.ss
index c7a6a3b..16adedb 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -404,6 +404,10 @@
     [bytevector-u8-set!      i]
     [bytevector-u16-ref         i]
     [bytevector-u16-set!        i]
+    [bytevector-u32-ref         i]
+    [bytevector-u32-set!        i]
+    [bytevector-s32-ref         i]
+    [bytevector-s32-set!        i]
     [bytevector-u16-native-ref  i]
     [bytevector-u16-native-set! i]
     [bytevector-s16-ref         i]
diff --git a/src/tests/bytevectors.ss b/src/tests/bytevectors.ss
index 11a82ac..c2a55a8 100644
--- a/src/tests/bytevectors.ss
+++ b/src/tests/bytevectors.ss
@@ -236,6 +236,49 @@
        (bytevector-s16-set! v 0 -12345 'big)
        (bytevector-s16-ref v 0 'big))]
 
+    [(lambda (x) (= x 4261412863))
+     (let ([v (u8-list->bytevector '(255 255 255 253))])
+       (bytevector-u32-ref v 0 'little))]
+    [(lambda (x) (= x 4294967293))
+     (let ([v (u8-list->bytevector '(255 255 255 253))])
+       (bytevector-u32-ref v 0 'big))]
+
+    [(lambda (x) (= x -33554433))
+     (let ([v (u8-list->bytevector '(255 255 255 253))])
+       (bytevector-s32-ref v 0 'little))]
+    [(lambda (x) (= x -3))
+     (let ([v (u8-list->bytevector '(255 255 255 253))])
+       (bytevector-s32-ref v 0 'big))]
+
+    [(lambda (x) (= x 12345))
+     (let ([v (make-bytevector 4)])
+       (bytevector-u32-set! v 0 12345 'little)
+       (bytevector-u32-ref v 0 'little))]
+    [(lambda (x) (= x 12345))
+     (let ([v (make-bytevector 4)])
+       (bytevector-u32-set! v 0 12345 'big)
+       (bytevector-u32-ref v 0 'big))]
+
+    [(lambda (x) (= x 12345))
+     (let ([v (make-bytevector 4)])
+       (bytevector-s32-set! v 0 12345 'little)
+       (bytevector-s32-ref v 0 'little))]
+    [(lambda (x) (= x 12345))
+     (let ([v (make-bytevector 4)])
+       (bytevector-s32-set! v 0 12345 'big)
+       (bytevector-s32-ref v 0 'big))]
+
+    [(lambda (x) (= x -12345))
+     (let ([v (make-bytevector 4)])
+       (bytevector-s32-set! v 0 -12345 'little)
+       (bytevector-s32-ref v 0 'little))]
+    [(lambda (x) (= x -12345))
+     (let ([v (make-bytevector 4)])
+       (bytevector-s32-set! v 0 -12345 'big)
+       (bytevector-s32-ref v 0 'big))]
+
+
+
 
 
 
diff --git a/src/todo-r6rs.ss b/src/todo-r6rs.ss
index 3d6fa8b..532a47b 100755
--- a/src/todo-r6rs.ss
+++ b/src/todo-r6rs.ss
@@ -370,8 +370,8 @@
     [bytevector-s16-set!                        C bv]
     [bytevector-s32-native-ref                  S bv]
     [bytevector-s32-native-set!                 S bv]
-    [bytevector-s32-ref                         S bv]
-    [bytevector-s32-set!                        S bv]
+    [bytevector-s32-ref                         C bv]
+    [bytevector-s32-set!                        C bv]
     [bytevector-s64-native-ref                  S bv]
     [bytevector-s64-native-set!                 S bv]
     [bytevector-s64-ref                         S bv]
@@ -386,8 +386,8 @@
     [bytevector-u16-set!                        C bv]
     [bytevector-u32-native-ref                  S bv]
     [bytevector-u32-native-set!                 S bv]
-    [bytevector-u32-ref                         S bv]
-    [bytevector-u32-set!                        S bv]
+    [bytevector-u32-ref                         C bv]
+    [bytevector-u32-set!                        C bv]
     [bytevector-u64-native-ref                  S bv]
     [bytevector-u64-native-set!                 S bv]
     [bytevector-u64-ref                         S bv]