--- a/ZipStream.st	Wed Jan 18 01:47:25 2017 +0100
+++ b/ZipStream.st	Wed Jan 18 01:48:38 2017 +0100
@@ -769,13 +769,15 @@
         on:aStream
         suppressHeaderAndChecksum:suppressZipHeaderAndChecksum.
 
-    suppressFileHeader ifFalse:[
-        self isReadable ifTrue:[
-            "Check for the gzip magic id"
-            self readHeader
-        ] ifFalse:[
-            "write the gzip magic id"
-            self writeHeader
+    suppressZipHeaderAndChecksum ifFalse:[    
+        suppressFileHeader ifFalse:[
+            self isReadable ifTrue:[
+                "Check for the gzip magic id"            
+                self readHeader
+            ] ifFalse:[
+                "write the gzip magic id"
+                self writeHeader
+            ].
         ].
     ].
 !