From eb5149fd0fd2e8f7216ba96386335da8a9261269 Mon Sep 17 00:00:00 2001
From: liquidraver <504870+liquidraver@users.noreply.github.com>
Date: Mon, 16 Mar 2026 11:49:12 +0100
Subject: [PATCH] fix BLE advert name for backwards compatibility

---
 zephcore/adapters/ble/ZephyrBLE.cpp         |  7 +++----
 zephcore/boards/common/zephcore_common.conf |  2 +-
 zephcore/src/main_companion.cpp             | 19 +++++++++----------
 3 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/zephcore/adapters/ble/ZephyrBLE.cpp b/zephcore/adapters/ble/ZephyrBLE.cpp
index 4e54654..3cfd02c 100644
--- a/zephcore/adapters/ble/ZephyrBLE.cpp
+++ b/zephcore/adapters/ble/ZephyrBLE.cpp
@@ -35,7 +35,7 @@ LOG_MODULE_REGISTER(zephcore_ble, CONFIG_ZEPHCORE_BLE_LOG_LEVEL);
 
 /* ========== Constants ========== */
 
-#define DEVICE_NAME_MAX 24
+#define DEVICE_NAME_MAX 29
 #define FRAME_QUEUE_SIZE CONFIG_ZEPHCORE_BLE_QUEUE_SIZE
 #define BLE_TX_POWER 4
 #define BLE_TX_RETRY_MS 20
@@ -230,9 +230,8 @@ static int secure_nus_send(struct bt_conn *conn, const void *data, uint16_t len)
 static void build_device_name_and_adv(const char *name_from_prefs)
 {
 	if (name_from_prefs && name_from_prefs[0]) {
-		size_t name_len = strnlen(name_from_prefs, sizeof(device_name) - 1);
-		memcpy(device_name, name_from_prefs, name_len);
-		device_name[name_len] = '\0';
+		/* Prepend "MeshCore-" prefix so apps that filter on it can find us */
+		snprintf(device_name, sizeof(device_name), "MeshCore-%s", name_from_prefs);
 
 		/* Apple BLE Accessory Design Guidelines: device name must not
 		 * contain ':' or ';' characters. Replace with '-'.
diff --git a/zephcore/boards/common/zephcore_common.conf b/zephcore/boards/common/zephcore_common.conf
index c41df1d..81152ca 100644
--- a/zephcore/boards/common/zephcore_common.conf
+++ b/zephcore/boards/common/zephcore_common.conf
@@ -66,7 +66,7 @@ CONFIG_BT_ZEPHYR_NUS=y
 CONFIG_BT_ZEPHYR_NUS_DEFAULT_INSTANCE=n
 CONFIG_BT_DEVICE_NAME="MeshCore"
 CONFIG_BT_DEVICE_NAME_DYNAMIC=y
-CONFIG_BT_DEVICE_NAME_MAX=24
+CONFIG_BT_DEVICE_NAME_MAX=29
 CONFIG_BT_DEVICE_NAME_GATT_WRITABLE=y
 CONFIG_BT_DEVICE_APPEARANCE=0
 CONFIG_BT_MAX_CONN=1
diff --git a/zephcore/src/main_companion.cpp b/zephcore/src/main_companion.cpp
index b65ae0f..0f03d14 100644
--- a/zephcore/src/main_companion.cpp
+++ b/zephcore/src/main_companion.cpp
@@ -546,16 +546,6 @@ int main(void)
 	companion_mesh.prefs.rx_duty_cycle = 1;     /* Companions: duty cycle ON by default (power save) */
 	companion_mesh.prefs.rx_boost = 1;          /* Default: boosted RX (+3dB sensitivity, +2mA) */
 
-	/* Generate default node name from hardware device ID */
-	uint8_t dev_id[8];
-	ssize_t id_len = hwinfo_get_device_id(dev_id, sizeof(dev_id));
-	if (id_len >= 4) {
-		snprintf(companion_mesh.prefs.node_name, sizeof(companion_mesh.prefs.node_name),
-			 "MeshCore-%02X%02X%02X%02X", dev_id[0], dev_id[1], dev_id[2], dev_id[3]);
-	} else {
-		strncpy(companion_mesh.prefs.node_name, "MeshCore", sizeof(companion_mesh.prefs.node_name) - 1);
-	}
-
 	/* Load prefs from storage */
 	data_store.loadPrefs(companion_mesh.prefs);
 
@@ -598,6 +588,15 @@ int main(void)
 	}
 	companion_mesh.self_id = self_identity;
 
+	/* Set default node name from first 4 bytes of public key if not set.
+	 * Must happen after identity load so pub_key is available. */
+	if (companion_mesh.prefs.node_name[0] == '\0') {
+		snprintf(companion_mesh.prefs.node_name, sizeof(companion_mesh.prefs.node_name),
+			 "%02X%02X%02X%02X",
+			 self_identity.pub_key[0], self_identity.pub_key[1],
+			 self_identity.pub_key[2], self_identity.pub_key[3]);
+	}
+
 	/* Set callbacks */
 	companion_mesh.setWriteFrameCallback(write_frame);
 	companion_mesh.setPushCallback(push_callback);