diff --git a/scheme/ikarus.io.ss b/scheme/ikarus.io.ss
index 2971628..e520b73 100644
--- a/scheme/ikarus.io.ss
+++ b/scheme/ikarus.io.ss
@@ -2267,7 +2267,7 @@
          (if (bytevector? bv) 
              (if (fixnum? i) 
                  (let ([n (bytevector-length bv)])
-                   (if (and (fx< i n) (fx>= i 0))
+                   (if (and (fx<= i n) (fx>= i 0))
                        ($put-bytevector p bv i (fx- n i))
                        (die 'put-bytevector "index out of range" i)))
                  (die 'put-bytevector "invalid index" i))
@@ -2276,7 +2276,7 @@
          (if (bytevector? bv) 
              (if (fixnum? i) 
                  (let ([n (bytevector-length bv)])
-                   (if (and (fx< i n) (fx>= i 0))
+                   (if (and (fx<= i n) (fx>= i 0))
                        (if (fixnum? c) 
                            (if (and (fx>= c 0) (fx>= (fx- n c) i))
                                ($put-bytevector p bv i c)
diff --git a/scheme/last-revision b/scheme/last-revision
index 197a77e..0fbe6bb 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1788
+1789