diff --git a/scheme/lib/uri.scm b/scheme/lib/uri.scm
index f9ed13c..1b38f8a 100644
--- a/scheme/lib/uri.scm
+++ b/scheme/lib/uri.scm
@@ -16,6 +16,8 @@
 
 (define uri-reserved (string->char-set ";/#?: ="))
 
+(define uri-reserved-sans-= (char-set-delete uri-reserved #\=))
+
 (define (parse-uri s)
   (let* ((slen (string-length s))
 	 ;; Search forwards for colon (or intervening reserved char).
@@ -29,10 +31,10 @@
 
 	 ;; Search backwards for ? (or intervening reserved char).
 	 ;; (NB: #\= may be after #\? and before #\#)
-	 (rs-penult (string-index-right
-		     s                      
-		     (char-set-delete uri-reserved #\=)
-		     (or sharp slen))) 
+	 (rs-penult (string-index-right s                      
+					uri-reserved-sans-=
+					path-start
+					(or sharp slen)))
 	 (ques (and rs-penult (char=? (string-ref s rs-penult) #\?) rs-penult))
 
 	 (path-end (or ques sharp slen)))