From 96dd454c0481bb8f1737ba3069ab2b7decd6e133 Mon Sep 17 00:00:00 2001
From: liquidraver <504870+liquidraver@users.noreply.github.com>
Date: Mon, 16 Mar 2026 10:58:57 +0100
Subject: [PATCH] fix transport code usage

---
 zephcore/helpers/TransportKeyStore.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/zephcore/helpers/TransportKeyStore.cpp b/zephcore/helpers/TransportKeyStore.cpp
index 76e4b5e..d37eccb 100644
--- a/zephcore/helpers/TransportKeyStore.cpp
+++ b/zephcore/helpers/TransportKeyStore.cpp
@@ -28,8 +28,8 @@ uint16_t TransportKey::calcTransportCode(const mesh::Packet* packet) const {
     mbedtls_md_hmac_finish(&ctx, hmac);
     mbedtls_md_free(&ctx);
 
-    /* Extract first 2 bytes as transport code */
-    uint16_t code = (hmac[0] << 8) | hmac[1];
+    /* Extract first 2 bytes as transport code (little-endian, matching Arduino SHA256 finalizeHMAC behavior) */
+    uint16_t code = (uint16_t)hmac[0] | ((uint16_t)hmac[1] << 8);
     if (code == 0) {       // reserve codes 0000 and FFFF
         code++;
     } else if (code == 0xFFFF) {