diff --git a/tinyipa/build-iso.sh b/tinyipa/build-iso.sh
index be0db45..13f93b3 100755
--- a/tinyipa/build-iso.sh
+++ b/tinyipa/build-iso.sh
@@ -2,14 +2,16 @@
 
 set -ex
 WORKDIR=$(readlink -f $0 | xargs dirname)
+SYSLINUX_VERSION="4.06"
+SYSLINUX_URL="https://www.kernel.org/pub/linux/utils/boot/syslinux/syslinux-${SYSLINUX_VERSION}.tar.gz"
 
 cd $WORKDIR/build_files
-wget -N https://www.kernel.org/pub/linux/utils/boot/syslinux/syslinux-4.06.tar.gz && tar zxf syslinux-4.06.tar.gz
+wget -N $SYSLINUX_URL && tar zxf syslinux-${SYSLINUX_VERSION}.tar.gz
 
 cd $WORKDIR
 rm -rf newiso
 mkdir -p newiso/boot/isolinux
-cp build_files/syslinux-4.06/core/isolinux.bin newiso/boot/isolinux/.
+cp build_files/syslinux-${SYSLINUX_VERSION}/core/isolinux.bin newiso/boot/isolinux/.
 cp build_files/isolinux.cfg newiso/boot/isolinux/.
 cp tinyipa.gz newiso/boot/corepure64.gz
 cp tinyipa.vmlinuz newiso/boot/vmlinuz64