diff --git a/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp b/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp
index 973ce688e..9a066e1ad 100644
--- a/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/aux_serial_driver.cpp
@@ -21,6 +21,7 @@
 #include "opentx.h"
 #include "targets/horus/board.h"
 
+#if defined(AUX_SERIAL)
 uint8_t auxSerialMode = 0;
 Fifo<uint8_t, 512> auxSerialTxFifo;
 
@@ -219,6 +220,7 @@ extern "C" void AUX_SERIAL_USART_IRQHandler(void)
     }
   }
 #endif
+
   // Receive
   uint32_t status = AUX_SERIAL_USART->SR;
   while (status & (USART_FLAG_RXNE | USART_FLAG_ERRORS)) {
@@ -231,9 +233,8 @@ extern "C" void AUX_SERIAL_USART_IRQHandler(void)
     }
     status = AUX_SERIAL_USART->SR;
   }
-#endif
 }
-#endif
+#endif // AUX_SERIAL
 
 #if defined(AUX2_SERIAL)
 uint8_t aux2SerialMode = 0;
@@ -378,7 +379,6 @@ uint8_t aux2SerialTracesEnabled()
 #endif
 }
 
-#if !defined(SIMU)
 extern "C" void AUX2_SERIAL_USART_IRQHandler(void)
 {
   DEBUG_INTERRUPT(INT_SER2);
@@ -411,7 +411,7 @@ extern "C" void AUX2_SERIAL_USART_IRQHandler(void)
     }
   }
 #endif
-#if defined(AUX2_SERIAL)
+
   // Receive
   uint32_t status = AUX2_SERIAL_USART->SR;
   while (status & (USART_FLAG_RXNE | USART_FLAG_ERRORS)) {
@@ -425,7 +425,4 @@ extern "C" void AUX2_SERIAL_USART_IRQHandler(void)
     status = AUX2_SERIAL_USART->SR;
   }
 }
-#endif
-
-#endif
-#endif // AUX_SERIAL
\ No newline at end of file
+#endif // AUX2_SERIAL
diff --git a/radio/src/thirdparty/libopenui b/radio/src/thirdparty/libopenui
index ec8dc7b3f..c877dbad7 160000
--- a/radio/src/thirdparty/libopenui
+++ b/radio/src/thirdparty/libopenui
@@ -1 +1 @@
-Subproject commit ec8dc7b3f152f547f7d65f20ed7cee85f71ab1c5
+Subproject commit c877dbad7823f306ed6273629bd256581a91b357