diff --git a/js/LoadSaveFile.js b/js/LoadSaveFile.js
index 9f3f90b..21f2235 100644
--- a/js/LoadSaveFile.js
+++ b/js/LoadSaveFile.js
@@ -1,4 +1,7 @@
-const CSHARP_HEADER = [0, 1, 0, 0, 0, 255, 255, 255, 255, 1, 0, 0, 0, 0, 0, 0, 0, 6, 1, 0, 0, 0];
+const CSHARP_HEADER = [0, 1, 0, 0, 0, 255, 255, 255, 255, 1, 0, 0, 0, 0, 0, 0, 0, 6, 1, 0, 0, 0]; // 22 bytes
+
+const BASE64_ARRAY = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".split("").map(c => c.charCodeAt(0));
+const BASE64_DECODE_TABLE = new Map(BASE64_ARRAY.map((ord, i) => [ord, i]));
 
 function ShowFile(input) {
     let inputFileObject = input.files[0];
@@ -25,7 +28,6 @@ function LoadSaveFile(input) {
 
     // 2. Decode file
 
-    // base64 Decoding (ArrayBuffer)
     // AES decryption (ECB) removes pkcs7 padding (ArrayBuffer)
     // Convert ArrayBuffer to string/text TextDecoder().decode(ArrayBuffer)
 
@@ -40,7 +42,7 @@ function FileObjectToArrayBuffer() {
     let inputArrayBuffer = this.result;
 
     try {
-        // Uint8Array(ArrayBuffer)
+        // Uint8Array(ArrayBuffer) uint8_t equivalent in C
         inputArrayBuffer = new Uint8Array(inputArrayBuffer);
 
         // ArrayBuffer.slice()
@@ -50,6 +52,9 @@ function FileObjectToArrayBuffer() {
         // remove C# header (ArrayBuffer)
         inputArrayBuffer = RemoveCSharpHeader(inputArrayBuffer);
 
+        // base64 Decoding (ArrayBuffer)
+        inputArrayBuffer = Base64Decode(inputArrayBuffer);
+
         alert(`File: ${inputArrayBuffer}`);
     } catch (error) {
         alert(`The file cannot be read. Error: ${error}`);
@@ -73,4 +78,30 @@ function RemoveCSharpHeader(buffer) {
     let fixedArrayBuffer = buffer.subarray(lengthCount);
 
     return fixedArrayBuffer;
+}
+
+// From bloodorca https://github.com/bloodorca/hollow based on KayDeeTee https://github.com/KayDeeTee/Hollow-Knight-SaveManager
+function Base64Decode(buffer) {
+    buffer = new Uint8Array(buffer).slice();
+    buffer = buffer.map(v => BASE64_DECODE_TABLE.get(v))
+    {
+        let p = buffer.indexOf(64);
+        buffer = buffer.subarray(0, p != -1 ? p : buffer.length);
+    }
+    let output = new Uint8Array(3 * buffer.length / 4);
+    let continuous = Math.floor(buffer.length / 4) * 4;
+    for (let i = 0; i < continuous; i += 4) {
+        let k = 3 * i / 4;
+        output[k] = buffer[i] << 2 | buffer[i + 1] >> 4;
+        output[k + 1] = (buffer[i + 1] & 0x0F) << 4 | buffer[i + 2] >> 2;
+        output[k + 2] = (buffer[i + 2] & 0x03) << 6 | buffer[i + 3];
+    }
+    if (buffer[continuous] != undefined) {
+        let k = 3 * continuous / 4;
+        output[k] = buffer[continuous] << 2 | buffer[continuous + 1] >> 4;
+        if (buffer[continuous + 2] != undefined) {
+            output[k + 1] = (buffer[continuous + 1] & 0x0F) << 4 | buffer[continuous + 2] >> 2;
+        }
+    }
+    return output;
 }
\ No newline at end of file