diff --git a/builder/family/realtek-ambz2.py b/builder/family/realtek-ambz2.py
index b3e2fd4..512f981 100644
--- a/builder/family/realtek-ambz2.py
+++ b/builder/family/realtek-ambz2.py
@@ -404,6 +404,12 @@ bootloader_dst = env.subst("${BUILD_DIR}/bootloader.axf")
 if not isfile(bootloader_dst):
     copyfile(bootloader_src, bootloader_dst)
 
+# OTA2 clearing - 4096 bytes of 0xFF
+image_ota_clear = env.subst("${BUILD_DIR}/raw_ota_clear.bin")
+if not isfile(image_ota_clear):
+    with open(image_ota_clear, "wb") as f:
+        f.write(b"\xFF" * 4096)
+
 # Build all libraries
 queue.BuildLibraries()
 
@@ -416,5 +422,7 @@ env.Replace(
     UF2OTA=[
         # same OTA images for flasher and device
         f"{image_firmware_is},{image_firmware_is}=device:ota1,ota2;flasher:ota1,ota2",
+        # clearing headers of the "other" OTA image (hence the indexes are swapped)
+        f"{image_ota_clear},{image_ota_clear}=device:ota2,ota1;flasher:ota2,ota1",
     ],
 )
diff --git a/cores/common/arduino/libraries/api/Serial/Serial.h b/cores/common/arduino/libraries/api/Serial/Serial.h
index da3bf02..232c48c 100644
--- a/cores/common/arduino/libraries/api/Serial/Serial.h
+++ b/cores/common/arduino/libraries/api/Serial/Serial.h
@@ -8,24 +8,30 @@
 
 using namespace arduino;
 
+#if HAS_SERIAL0
 #ifndef PIN_SERIAL0_RX
 #define PIN_SERIAL0_RX PIN_INVALID
 #endif
-#ifndef PIN_SERIAL1_RX
-#define PIN_SERIAL1_RX PIN_INVALID
-#endif
-#ifndef PIN_SERIAL2_RX
-#define PIN_SERIAL2_RX PIN_INVALID
-#endif
 #ifndef PIN_SERIAL0_TX
 #define PIN_SERIAL0_TX PIN_INVALID
 #endif
+#endif
+#if HAS_SERIAL1
+#ifndef PIN_SERIAL1_RX
+#define PIN_SERIAL1_RX PIN_INVALID
+#endif
 #ifndef PIN_SERIAL1_TX
 #define PIN_SERIAL1_TX PIN_INVALID
 #endif
+#endif
+#if HAS_SERIAL2
+#ifndef PIN_SERIAL2_RX
+#define PIN_SERIAL2_RX PIN_INVALID
+#endif
 #ifndef PIN_SERIAL2_TX
 #define PIN_SERIAL2_TX PIN_INVALID
 #endif
+#endif
 
 class SerialClass : public HardwareSerial {
   private:
diff --git a/cores/realtek-ambz2/arduino/libraries/Serial/Serial.cpp b/cores/realtek-ambz2/arduino/libraries/Serial/Serial.cpp
index eb1e462..3b69859 100644
--- a/cores/realtek-ambz2/arduino/libraries/Serial/Serial.cpp
+++ b/cores/realtek-ambz2/arduino/libraries/Serial/Serial.cpp
@@ -33,10 +33,6 @@ void SerialClass::begin(unsigned long baudrate, uint16_t config) {
 		this->data = new SerialData();
 		this->buf  = &BUF;
 
-		if (this->port == 2) {
-			hal_uart_deinit(&log_uart);
-		}
-
 		// TODO handle PIN_INVALID
 		hal_uart_init(&UART, this->tx, this->rx, NULL);