diff --git a/firmware/esp32/overland-controller/config.h b/firmware/esp32/overland-controller/config.h
index 724eda2..3697ff8 100644
--- a/firmware/esp32/overland-controller/config.h
+++ b/firmware/esp32/overland-controller/config.h
@@ -33,3 +33,6 @@
 
 // LilyGO bring-up isolation: disable BLE/BMS to test WiFi AP stability.
 #define BMS_COMPILE_ENABLED 0
+
+// LilyGO S3 WiFi isolation: use AP-only mode, no STA.
+#define LILYGO_SIMPLE_AP_ONLY_DEBUG 1
diff --git a/firmware/esp32/overland-controller/overland-controller.ino b/firmware/esp32/overland-controller/overland-controller.ino
index e6db5ae..e5e478f 100644
--- a/firmware/esp32/overland-controller/overland-controller.ino
+++ b/firmware/esp32/overland-controller/overland-controller.ino
@@ -2067,6 +2067,10 @@ int findNextWifiIndexByPriority(bool tried[]) {
 }
 
 void connectStaWifi() {
+#if LILYGO_SIMPLE_AP_ONLY_DEBUG
+    Serial.println("STA WiFi disabled for LilyGO AP-only debug.");
+    return;
+#endif
     if (wifiNetworkCount <= 0) {
         Serial.println("STA WiFi not configured.");
         return;
@@ -4152,7 +4156,13 @@ void setup() {
     loadApConfig();
     heapCheckpoint("after:loadApConfig");
 
+#if LILYGO_SIMPLE_AP_ONLY_DEBUG
+    WiFi.persistent(false);
+    WiFi.setSleep(false);
+    WiFi.mode(WIFI_AP);
+#else
     WiFi.mode(WIFI_AP_STA);
+#endif
     startAccessPoint();
     oledShowSetupPage();