diff --git a/nuttx-configs/px4fmu-v4/nsh/defconfig b/nuttx-configs/px4fmu-v4/nsh/defconfig
index f3f4d51c7f..0b26f204c4 100644
--- a/nuttx-configs/px4fmu-v4/nsh/defconfig
+++ b/nuttx-configs/px4fmu-v4/nsh/defconfig
@@ -965,7 +965,7 @@ 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-v4pro/nsh/defconfig b/nuttx-configs/px4fmu-v4pro/nsh/defconfig
index 2594d00b3b..40b6f7bfba 100644
--- a/nuttx-configs/px4fmu-v4pro/nsh/defconfig
+++ b/nuttx-configs/px4fmu-v4pro/nsh/defconfig
@@ -990,7 +990,7 @@ 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