diff --git a/lib/util-iso.sh b/lib/util-iso.sh
index bf30c2d..66fbfea 100644
--- a/lib/util-iso.sh
+++ b/lib/util-iso.sh
@@ -138,8 +138,10 @@ make_sfs() {
     mksfs_args+=(${sfs} -noappend)
 
     local highcomp="-b 256K -Xbcj x86"
-   # local comp='xz'
-    [[ "${iso_compression}" != "xz" ]] || [[ "${iso_compression}" != "zstd" ]] && highcomp=""
+
+    [[ "${iso_compression}" != "xz" ]] && highcomp=""
+    
+    [[ "${iso_compression}" == "zstd" ]] && highcomp=""
 
     if [[ "${name}" == "mhwdfs" && ${used_kernel} < "4" ]]; then
         mksfs_args+=(-comp lz4)