diff --git a/lib/zonefile-node-legacy.js b/lib/zonefile-node-legacy.js
index c450ea9..2e5e6ff 100644
--- a/lib/zonefile-node-legacy.js
+++ b/lib/zonefile-node-legacy.js
@@ -271,20 +271,14 @@ let removeComments = function (text) {
 };
 
 let flatten = function (text) {
-  let captured = [];
-  let re = /\([\s\S]*?\)/gim;
+  let soa;
+  let re = /SOA[\s\S]*?\([\s\S]*?\)/gim;
   let match = re.exec(text);
-  while (match !== null) {
-    match.replacement = match[0].replace(/\s+/gm, ' ');
-    captured.push(match);
-    // captured Text, index, input
-    match = re.exec(text);
+  if (match !== null) {
+    soa = match[0].replace(/\s+/gm, ' ');
   }
-  let arrText = text.split('');
-  for (match of captured) {
-    arrText.splice(match.index, match[0].length, match.replacement);
-  }
-  return arrText.join('').replace(/\(|\)/gim, ' ');
+  soa = soa.replace(/\(|\)/gim, ' ');
+  return text.substring(0, match.index) + soa + text.substring(match.index + match[0].length);
 };
 
 let normalizeRR = function (rr) {
diff --git a/lib/zonefile.js b/lib/zonefile.js
index 933ab7a..9ebf275 100644
--- a/lib/zonefile.js
+++ b/lib/zonefile.js
@@ -270,20 +270,14 @@ let removeComments = function (text) {
 };
 
 let flatten = function (text) {
-  let captured = [];
-  let re = /\([\s\S]*?\)/gim;
+  let soa;
+  let re = /SOA[\s\S]*?\([\s\S]*?\)/gim;
   let match = re.exec(text);
-  while (match !== null) {
-    match.replacement = match[0].replace(/\s+/gm, ' ');
-    captured.push(match);
-    // captured Text, index, input
-    match = re.exec(text);
+  if (match !== null) {
+    soa = match[0].replace(/\s+/gm, ' ');
   }
-  let arrText = text.split('');
-  for (match of captured) {
-    arrText.splice(match.index, match[0].length, match.replacement);
-  }
-  return arrText.join('').replace(/\(|\)/gim, ' ');
+  soa = soa.replace(/\(|\)/gim, ' ');
+  return text.substring(0, match.index) + soa + text.substring(match.index + match[0].length);
 };
 
 let normalizeRR = function (rr) {
diff --git a/package.json b/package.json
index 76b070f..34718ee 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "dns-zonefile",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "description": "A DNS zone file parser and generator.",
   "main": "./lib/zonefile.js",
   "types": "./lib/zonefile.d.ts",