diff --git a/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig b/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
index 94353df976..34e91912d4 100644
--- a/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
+++ b/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
@@ -258,6 +258,7 @@ CONFIG_UART4_TXBUFSIZE=1500
 CONFIG_UART5_IFLOWCONTROL=y
 CONFIG_UART5_OFLOWCONTROL=y
 CONFIG_UART5_RXDMA=y
+CONFIG_UART5_TXBUFSIZE=3000
 CONFIG_UART5_TXDMA=y
 CONFIG_UART7_BAUD=57600
 CONFIG_UART7_IFLOWCONTROL=y