diff --git a/scheme/ikarus.pretty-formats.ss b/scheme/ikarus.pretty-formats.ss
index 24d2bc0..6cdf54e 100644
--- a/scheme/ikarus.pretty-formats.ss
+++ b/scheme/ikarus.pretty-formats.ss
@@ -31,7 +31,7 @@
       (unless (symbol? x)
         (die 'pretty-format "not a symbol" x))
       (case-lambda
-        [() (hashtable-ref h x)]
+        [() (hashtable-ref h x #f)]
         [(v) (hashtable-set! h x v)])))
 
   ;;; standard formats
diff --git a/scheme/ikarus.writer.ss b/scheme/ikarus.writer.ss
index 21535d1..1496f47 100644
--- a/scheme/ikarus.writer.ss
+++ b/scheme/ikarus.writer.ss
@@ -462,8 +462,8 @@
             (let ([p (get-fmt a)])
               (and (pair? p)
                 (eq? (car p) 'read-macro)
-                (string? (cdr p)))
-                p))))))
+                (string? (cdr p))
+                p)))))))
   
   (define write-pair
     (lambda (x p m h i)
diff --git a/scheme/last-revision b/scheme/last-revision
index 3c074e4..0d4b7f5 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1475
+1476