diff --git a/SerialSTM.cpp b/SerialSTM.cpp
index 3762f92..d8dd0d7 100644
--- a/SerialSTM.cpp
+++ b/SerialSTM.cpp
@@ -41,8 +41,8 @@ USART2 - TXD PA2  - RXD PA3
 
 */
 
-#define TX_SERIAL_FIFO_SIZE 256U
-#define RX_SERIAL_FIFO_SIZE 256U
+#define TX_SERIAL_FIFO_SIZE 512U
+#define RX_SERIAL_FIFO_SIZE 512U
 
 #if defined(STM32_USART1_HOST)