diff --git a/configs/releng/build.sh b/configs/releng/build.sh
index 3a105df..419ad7d 100755
--- a/configs/releng/build.sh
+++ b/configs/releng/build.sh
@@ -140,8 +140,8 @@ make_syslinux() {
     cp ${work_dir}/x86_64/airootfs/usr/lib/syslinux/bios/lpxelinux.0 ${work_dir}/iso/${install_dir}/boot/syslinux
     cp ${work_dir}/x86_64/airootfs/usr/lib/syslinux/bios/memdisk ${work_dir}/iso/${install_dir}/boot/syslinux
     mkdir -p ${work_dir}/iso/${install_dir}/boot/syslinux/hdt
-    gzip -c -9 ${work_dir}/x86_64/airootfs/usr/share/hwdata/pci.ids > ${work_dir}/iso/${install_dir}/boot/syslinux/hdt/pciids.gz
-    gzip -c -9 ${work_dir}/x86_64/airootfs/usr/lib/modules/${_uname_r}/modules.alias > ${work_dir}/iso/${install_dir}/boot/syslinux/hdt/modalias.gz
+    gzip -nc -9 ${work_dir}/x86_64/airootfs/usr/share/hwdata/pci.ids > ${work_dir}/iso/${install_dir}/boot/syslinux/hdt/pciids.gz
+    gzip -nc -9 ${work_dir}/x86_64/airootfs/usr/lib/modules/${_uname_r}/modules.alias > ${work_dir}/iso/${install_dir}/boot/syslinux/hdt/modalias.gz
 }
 
 # Prepare /isolinux