diff --git a/server.ts b/server.ts
index 80268d0..14aad4d 100644
--- a/server.ts
+++ b/server.ts
@@ -27,12 +27,13 @@ Deno.serve({ port: Number(Deno.env.get('PORT') ?? 8000) }, async (req) => {
 
 	if (response.ok) {
 		// Update content-type if not bin file
-		if (response.headers.get('Content-Type') !== 'application/octet-stream') {
-			response.headers.set('Content-Type', mimeType)
+		const headers = new Headers(response.headers)
+		if (headers.get('Content-Type') !== 'application/octet-stream') {
+			headers.set('Content-Type', mimeType)
 		}
 
 		// Stream original file to user
-		return response
+		return new Response(response.body, { headers })
 	}
 
 	return response