diff --git a/zlib.spec b/zlib.spec
index 0327f63..03f5469 100644
--- a/zlib.spec
+++ b/zlib.spec
@@ -110,20 +110,15 @@ mv ChangeLog.tmp ChangeLog
 
 
 %build
-export CFLAGS="$RPM_OPT_FLAGS"
-%ifarch s390 s390x
-CFLAGS+=" -DDFLTCC"
-%endif
-
-export MKFLAGS=""
-%ifarch s390 s390x
-MKFLAGS+="OBJA=dfltcc.o PIC_OBJA=dfltcc.lo"
-%endif
 
 export LDFLAGS="$LDFLAGS -Wl,-z,relro -Wl,-z,now"
 # no-autotools, %%configure is not compatible
-./configure --libdir=%{_libdir} --includedir=%{_includedir} --prefix=%{_prefix}
-%make_build $MKFLAGS
+%ifarch s390 s390x
+  ./configure --libdir=%{_libdir} --includedir=%{_includedir} --prefix=%{_prefix} --dfltcc
+%else
+  ./configure --libdir=%{_libdir} --includedir=%{_includedir} --prefix=%{_prefix}
+%endif
+%make_build
 
 %if %{with minizip}
 cd contrib/minizip
@@ -186,6 +181,7 @@ find $RPM_BUILD_ROOT -name '*.la' -delete
 %changelog
 * Thu Jun 03 2021 Patrik Novotný <panovotn@redhat.com> - 1.2.11-28
 - IBM CRC32 optimalization rhbz#1959423
+- Enabled Z hardware-accelerated deflate for compression levels 1 through 6 (#1972057)
 
 * Fri Apr 16 2021 Mohan Boddu <mboddu@redhat.com> - 1.2.11-27
 - Rebuilt for RHEL 9 BETA on Apr 15th 2021. Related: rhbz#1947937