diff --git a/esphome/nspanel_esphome_core.yaml b/esphome/nspanel_esphome_core.yaml
index 075080b..9ca3a83 100644
--- a/esphome/nspanel_esphome_core.yaml
+++ b/esphome/nspanel_esphome_core.yaml
@@ -1709,11 +1709,15 @@ text_sensor:
       if (!${pre_built}) {
         return {"${name}"};
         } else {
-        uint8_t mac[6] = {0};
-        esp_err_t ret = ESP_OK;
-        ret = esp_read_mac(mac, ESP_MAC_WIFI_STA);
-        std::string suffix = std::string(mac[3],16) + std::string(mac[4],16) + std::string(mac[5],16);
-        return {"${name}-" + suffix};
+        std::string suffix;
+        uint8_t mac[6] = {0,0,0,0,0,0};
+        esp_read_mac(mac, ESP_MAC_WIFI_STA);
+        for (int i = 3; i < 6; ++i) {
+          char hex[3];
+          snprintf(hex, sizeof(hex), "%02X", mac[i]);
+          suffix += hex;
+        }
+        return {"${name}" + "-" + suffix};
         }
     filters:
       - lambda: |-