diff -up Archive-Zip-1.39/lib/Archive/Zip/Member.pm.orig Archive-Zip-1.39/lib/Archive/Zip/Member.pm
--- Archive-Zip-1.39/lib/Archive/Zip/Member.pm.orig	2014-10-22 13:05:47.852592106 +0200
+++ Archive-Zip-1.39/lib/Archive/Zip/Member.pm	2014-10-22 13:10:28.151696108 +0200
@@ -159,16 +159,16 @@ sub bitFlag {
 # Set General Purpose Bit Flags according to the desiredCompressionLevel setting
     if (   $self->desiredCompressionLevel == 1
         || $self->desiredCompressionLevel == 2) {
-        $self->{'bitFlag'} = DEFLATING_COMPRESSION_FAST;
+        $self->{'bitFlag'} |= DEFLATING_COMPRESSION_FAST;
     } elsif ($self->desiredCompressionLevel == 3
         || $self->desiredCompressionLevel == 4
         || $self->desiredCompressionLevel == 5
         || $self->desiredCompressionLevel == 6
         || $self->desiredCompressionLevel == 7) {
-        $self->{'bitFlag'} = DEFLATING_COMPRESSION_NORMAL;
+        $self->{'bitFlag'} |= DEFLATING_COMPRESSION_NORMAL;
     } elsif ($self->desiredCompressionLevel == 8
         || $self->desiredCompressionLevel == 9) {
-        $self->{'bitFlag'} = DEFLATING_COMPRESSION_MAXIMUM;
+        $self->{'bitFlag'} |= DEFLATING_COMPRESSION_MAXIMUM;
     }
 
     if ($Archive::Zip::UNICODE) {