diff --git a/src/external-patches/firefox/issue_14990.patch b/src/external-patches/firefox/issue_14990.patch
index 0a0615c9b..7f90b2a51 100644
--- a/src/external-patches/firefox/issue_14990.patch
+++ b/src/external-patches/firefox/issue_14990.patch
@@ -54,7 +54,7 @@ diff --git a/browser/components/sessionstore/SessionWriter.sys.mjs b/browser/com
 +        uncompressedBytes = await IOUtils.writeJSON(this.Paths.clean, state, {
            tmpPath: this.Paths.clean + ".tmp",
            compress: true,
-+          jsonLengthHint,
++          lengthHint: jsonLengthHint,
          });
          fileStat = await IOUtils.stat(this.Paths.clean);
        } else if (this.state == STATE_RECOVERY) {
@@ -69,7 +69,7 @@ diff --git a/browser/components/sessionstore/SessionWriter.sys.mjs b/browser/com
            tmpPath: this.Paths.recovery + ".tmp",
            backupFile: this.Paths.recoveryBackup,
            compress: true,
-+          jsonLengthHint,
++          lengthHint: jsonLengthHint,
          });
          fileStat = await IOUtils.stat(this.Paths.recovery);
        } else {
@@ -80,7 +80,7 @@ diff --git a/browser/components/sessionstore/SessionWriter.sys.mjs b/browser/com
 +        uncompressedBytes = await IOUtils.writeJSON(this.Paths.recovery, state, {
            tmpPath: this.Paths.recovery + ".tmp",
            compress: true,
-+          jsonLengthHint,
++          lengthHint: jsonLengthHint,
          });
          fileStat = await IOUtils.stat(this.Paths.recovery);
        }
diff --git a/src/external-patches/manifest.json b/src/external-patches/manifest.json
index a3b9d2613..bede642e2 100644
--- a/src/external-patches/manifest.json
+++ b/src/external-patches/manifest.json
@@ -45,7 +45,8 @@
     "id": "D298708",
     "name": "Issue 14990",
     "replaces": {
-      "this._lastJsonLength = uncompressedBytes;": "this._lastJsonLength = uncompressedBytes.jsonLength;"
+      "this._lastJsonLength = uncompressedBytes;": "this._lastJsonLength = uncompressedBytes.jsonLength;",
+      "          jsonLengthHint,": "          lengthHint: jsonLengthHint,"
     }
   }
 ]
diff --git a/src/toolkit/modules/JSONFile-sys-mjs.patch b/src/toolkit/modules/JSONFile-sys-mjs.patch
index 376848f1b..ca27e90bc 100644
--- a/src/toolkit/modules/JSONFile-sys-mjs.patch
+++ b/src/toolkit/modules/JSONFile-sys-mjs.patch
@@ -1,5 +1,5 @@
 diff --git a/toolkit/modules/JSONFile.sys.mjs b/toolkit/modules/JSONFile.sys.mjs
-index 397991e4af8f49b6365d729fc11267b5c1113400..70da83a0dd7658986dfd5f52103873bbb33b3c18 100644
+index 397991e4af8f49b6365d729fc11267b5c1113400..599ed16981aa1f1e9abfee2ad6c1883efd88e0ba 100644
 --- a/toolkit/modules/JSONFile.sys.mjs
 +++ b/toolkit/modules/JSONFile.sys.mjs
 @@ -132,6 +132,7 @@ export function JSONFile(config) {
@@ -16,7 +16,7 @@ index 397991e4af8f49b6365d729fc11267b5c1113400..70da83a0dd7658986dfd5f52103873bb
      try {
 -      await IOUtils.writeJSON(
 +      if (this._useSizeHints && this._lastSavedSize) {
-+        this._options.jsonLengthHint = Math.ceil(this._lastSavedSize * 1.05);
++        this._options.lengthHint = Math.ceil(this._lastSavedSize * 1.05);
 +      }
 +      const result = await IOUtils.writeJSON(
          this.path,