diff --git a/ESP32_CAN_Logger-a.ino b/ESP32_CAN_Logger-a.ino
index 4c5ad73..43efb6f 100644
--- a/ESP32_CAN_Logger-a.ino
+++ b/ESP32_CAN_Logger-a.ino
@@ -688,8 +688,8 @@ void applySerialSettings() {
         else config = SERIAL_8O1;
     }
     if (serialSettings.stopBits == 2) config |= 0x3000;
+    SerialComm.setRxBufferSize(2048);  // ★ begin() 전에 호출 필수 (ESP32)
     SerialComm.begin(serialSettings.baudRate, config, SERIAL_RX_PIN, SERIAL_TX_PIN);
-    SerialComm.setRxBufferSize(2048);
 
     uint32_t config2 = SERIAL_8N1;
     if (serial2Settings.dataBits == 5) {
@@ -710,8 +710,8 @@ void applySerialSettings() {
         else config2 = SERIAL_8O1;
     }
     if (serial2Settings.stopBits == 2) config2 |= 0x3000;
+    Serial2Comm.setRxBufferSize(2048);  // ★ begin() 전에 호출 필수 (ESP32)
     Serial2Comm.begin(serial2Settings.baudRate, config2, SERIAL2_RX_PIN, SERIAL2_TX_PIN);
-    Serial2Comm.setRxBufferSize(2048);
 }
 
 // ========================================
@@ -1142,8 +1142,9 @@ void canRxTask(void *parameter) {
             // 읽기 완료 후 즉시 다음 폴링 (loop 재진입)
         } else {
             // INT HIGH, 플래그도 없음 → 타 태스크에 CPU 양보
-            // ★ vTaskDelay 사용 금지: delay 중 HW 오버플로우 가능
-            taskYIELD();
+            // ★ vTaskDelay(1) 사용: taskYIELD()는 동일 우선순위에만 양보하므로
+            //   하위 우선순위 태스크(Serial RX 등)가 CPU를 받을 수 없음
+            vTaskDelay(pdMS_TO_TICKS(1));
         }
     }
 }
@@ -1618,6 +1619,7 @@ void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length)
         DynamicJsonDocument doc(44384);
         if (deserializeJson(doc, payload)) return;
         const char* cmd = doc["cmd"];
+        if (!cmd) return;  // ★ cmd 없는 메시지 무시 (NULL strcmp 크래시 방지)
 
         if (strcmp(cmd, "getSettings") == 0) {
             DynamicJsonDocument r(1024);
@@ -1765,6 +1767,14 @@ void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length)
             serialSettings.stopBits = doc["stopBits"]  | 1;
             saveSerialSettings(); applySerialSettings();
         }
+        else if (strcmp(cmd, "setSerialBaud") == 0) {
+            // ★ JS applySettings()에서 전송하는 커맨드 지원
+            serialSettings.baudRate = doc["baud"] | 115200;
+            saveSerialSettings(); applySerialSettings();
+            char resp[128];
+            snprintf(resp, sizeof(resp), "{\"type\":\"serialConfig\",\"baudRate\":%u}", serialSettings.baudRate);
+            webSocket.sendTXT(num, resp);
+        }
         else if (strcmp(cmd, "getSerialConfig") == 0) {
             DynamicJsonDocument r(512);
             r["type"]="serialConfig"; r["baudRate"]=serialSettings.baudRate;
@@ -1836,6 +1846,14 @@ void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length)
             serial2Settings.stopBits = doc["stopBits"]  | 1;
             saveSerialSettings(); applySerialSettings();
         }
+        else if (strcmp(cmd, "setSerial2Baud") == 0) {
+            // ★ JS applySettings()에서 전송하는 커맨드 지원
+            serial2Settings.baudRate = doc["baud"] | 115200;
+            saveSerialSettings(); applySerialSettings();
+            char resp[128];
+            snprintf(resp, sizeof(resp), "{\"type\":\"serial2Config\",\"baudRate\":%u}", serial2Settings.baudRate);
+            webSocket.sendTXT(num, resp);
+        }
         else if (strcmp(cmd, "getSerial2Config") == 0) {
             DynamicJsonDocument r(512);
             r["type"]="serial2Config"; r["baudRate"]=serial2Settings.baudRate;
@@ -2675,8 +2693,8 @@ void setup() {
     xTaskCreatePinnedToCore(sdMonitorTask, "SD_MONITOR",  4096, NULL,  1, NULL,                  1);
     xTaskCreatePinnedToCore(sdFlushTask,   "SD_FLUSH",    4096, NULL,  9, &sdFlushTaskHandle,    0);
     xTaskCreatePinnedToCore(sdWriteTask,   "SD_WRITE",   18576, NULL,  8, &sdWriteTaskHandle,    0);
-    xTaskCreatePinnedToCore(serialRxTask,  "SERIAL_RX",   6144, NULL,  6, &serialRxTaskHandle,   1);
-    xTaskCreatePinnedToCore(serial2RxTask, "SERIAL2_RX",  6144, NULL,  6, &serial2RxTaskHandle,  1);
+    xTaskCreatePinnedToCore(serialRxTask,  "SERIAL_RX",   6144, NULL,  6, &serialRxTaskHandle,   0);
+    xTaskCreatePinnedToCore(serial2RxTask, "SERIAL2_RX",  6144, NULL,  6, &serial2RxTaskHandle,  0);
     if (timeSyncStatus.rtcAvailable)
         xTaskCreatePinnedToCore(rtcSyncTask,"RTC_SYNC",   3072, NULL,  0, &rtcTaskHandle,        0);
     // ★ canRxTask 마지막 생성 (Core 1 Pri 24 → 이 시점엔 setup() 완료 직전)
@@ -2687,10 +2705,10 @@ void setup() {
     Serial.println("========================================");
     Serial.println("Core 1:");
     Serial.printf("  CAN_RX     Pri 24 → canRing    (SPSC push, no mutex)\n");
-    Serial.printf("  WEB_UPDATE Pri  8 ← serialRing (SPSC pop,  no mutex)\n");
     Serial.printf("  TX/SEQ/MON Pri 3/2/1\n");
     Serial.println("Core 0:");
     Serial.printf("  SD_FLUSH   Pri  9 (Double Buffer 비동기 flush)\n");
+    Serial.printf("  WEB_UPDATE Pri  8 ← serialRing (SPSC pop,  no mutex)\n");
     Serial.printf("  SD_WRITE   Pri  8 ← canRing    (SPSC pop,  BIN no mutex)\n");
     Serial.printf("  SERIAL_RX  Pri  6 → serialRing (SPSC push)\n");
     Serial.printf("  SERIAL2_RX Pri  6 → serial2Ring(SPSC push)\n");
diff --git a/serial_terminal.h b/serial_terminal.h
index c1bccdf..b17a83d 100644
--- a/serial_terminal.h
+++ b/serial_terminal.h
@@ -549,9 +549,12 @@ const char serial_terminal_html[] PROGMEM = R"rawliteral(
                     } else if (data.type === 'serialStatus' || data.type === 'update') {
                         updateStatus(data);
                     } else if (data.type === 'pong') {
-                        // keepalive                    } else if (data.type === 'usbMirrorState') {
+                        // keepalive
+                    } else if (data.type === 'usbMirrorState') {
                         usbMirrorEnabled = data.enabled;
                         updateToggle('btn-usbmirror', usbMirrorEnabled, '🔌 USB Mirror');
+                    } else if (data.type === 'webLog') {
+                        showWebLog(data.msg);
                     }
                 } catch (e) {
                     console.error('Parse error:', e);