diff --git a/scripts/bundle-a2ui.sh b/scripts/bundle-a2ui.sh
index a1cf7ff2b..8c7d05fd0 100755
--- a/scripts/bundle-a2ui.sh
+++ b/scripts/bundle-a2ui.sh
@@ -30,11 +30,10 @@ collect_files() {
 }
 
 compute_hash() {
+  # Use Node.js for cross-platform hash computation (works on Windows, macOS, Linux)
   collect_files \
     | LC_ALL=C sort -z \
-    | xargs -0 shasum -a 256 \
-    | shasum -a 256 \
-    | awk '{print $1}'
+    | xargs -0 node "$ROOT_DIR/scripts/compute-file-hash.mjs"
 }
 
 current_hash="$(compute_hash)"
diff --git a/scripts/compute-file-hash.mjs b/scripts/compute-file-hash.mjs
new file mode 100755
index 000000000..3cdeff176
--- /dev/null
+++ b/scripts/compute-file-hash.mjs
@@ -0,0 +1,19 @@
+#!/usr/bin/env node
+import { createHash } from "node:crypto";
+import { readFileSync } from "node:fs";
+
+// Compute SHA-256 hash of all input files (cross-platform)
+const files = process.argv.slice(2);
+const hash = createHash("sha256");
+
+for (const file of files) {
+  try {
+    const content = readFileSync(file);
+    hash.update(content);
+  } catch (err) {
+    // Skip files that don't exist or can't be read
+    process.stderr.write(`Warning: Could not read ${file}: ${err.message}\n`);
+  }
+}
+
+console.log(hash.digest("hex"));