diff --git a/boards/px4/fmu-v4/nuttx-config/nsh/defconfig b/boards/px4/fmu-v4/nuttx-config/nsh/defconfig
index dabdbf7abb..c7136768bf 100644
--- a/boards/px4/fmu-v4/nuttx-config/nsh/defconfig
+++ b/boards/px4/fmu-v4/nuttx-config/nsh/defconfig
@@ -225,9 +225,9 @@ CONFIG_USART2_TXBUFSIZE=1100
 CONFIG_USART3_BAUD=57600
 CONFIG_USART3_IFLOWCONTROL=y
 CONFIG_USART3_OFLOWCONTROL=y
-CONFIG_USART3_RXBUFSIZE=300
+CONFIG_USART3_RXBUFSIZE=1200
 CONFIG_USART3_RXDMA=y
-CONFIG_USART3_TXBUFSIZE=600
+CONFIG_USART3_TXBUFSIZE=900
 CONFIG_USART6_BAUD=57600
 CONFIG_USART6_RXBUFSIZE=300
 CONFIG_USART6_RXDMA=y