diff --git a/nuttx-configs/px4fmu-v2/nsh/defconfig b/nuttx-configs/px4fmu-v2/nsh/defconfig
index 2a57809a96..ba83573590 100644
--- a/nuttx-configs/px4fmu-v2/nsh/defconfig
+++ b/nuttx-configs/px4fmu-v2/nsh/defconfig
@@ -981,7 +981,7 @@ CONFIG_USART2_OFLOWCONTROL=y
 # USART3 Configuration
 #
 CONFIG_USART3_RXBUFSIZE=300
-CONFIG_USART3_TXBUFSIZE=300
+CONFIG_USART3_TXBUFSIZE=600
 CONFIG_USART3_BAUD=57600
 CONFIG_USART3_BITS=8
 CONFIG_USART3_PARITY=0
diff --git a/nuttx-configs/px4fmu-v3/nsh/defconfig b/nuttx-configs/px4fmu-v3/nsh/defconfig
index 2a57809a96..ba83573590 100644
--- a/nuttx-configs/px4fmu-v3/nsh/defconfig
+++ b/nuttx-configs/px4fmu-v3/nsh/defconfig
@@ -981,7 +981,7 @@ CONFIG_USART2_OFLOWCONTROL=y
 # USART3 Configuration
 #
 CONFIG_USART3_RXBUFSIZE=300
-CONFIG_USART3_TXBUFSIZE=300
+CONFIG_USART3_TXBUFSIZE=600
 CONFIG_USART3_BAUD=57600
 CONFIG_USART3_BITS=8
 CONFIG_USART3_PARITY=0