diff --git a/addons/xterm-addon-search/src/SearchAddon.api.ts b/addons/xterm-addon-search/src/SearchAddon.api.ts
index f970fcc8..186cccca 100644
--- a/addons/xterm-addon-search/src/SearchAddon.api.ts
+++ b/addons/xterm-addon-search/src/SearchAddon.api.ts
@@ -113,7 +113,7 @@ async function openTerminal(options: ITerminalOptions = {}): Promise<void> {
 async function writeSync(data: string): Promise<void> {
   await page.evaluate(`window.term.write('${data}');`);
   while (true) {
-    if (await page.evaluate(`window.term._core.writeBuffer.length === 0`)) {
+    if (await page.evaluate(`window.term._core._writeBuffer.length === 0`)) {
       break;
     }
   }
diff --git a/addons/xterm-addon-webgl/src/WebglRenderer.api.ts b/addons/xterm-addon-webgl/src/WebglRenderer.api.ts
index b26790c4..82ac0adf 100644
--- a/addons/xterm-addon-webgl/src/WebglRenderer.api.ts
+++ b/addons/xterm-addon-webgl/src/WebglRenderer.api.ts
@@ -147,7 +147,7 @@ async function openTerminal(options: ITerminalOptions = {}): Promise<void> {
 async function writeSync(data: string): Promise<void> {
   await page.evaluate(`window.term.write('${data}');`);
   while (true) {
-    if (await page.evaluate(`window.term._core.writeBuffer.length === 0`)) {
+    if (await page.evaluate(`window.term._core._writeBuffer.length === 0`)) {
       break;
     }
   }