diff --git a/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig b/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig
index f949d32dc4..38deab0e43 100644
--- a/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig
+++ b/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig
@@ -296,6 +296,7 @@ CONFIG_UART4_RXBUFSIZE=600
 CONFIG_UART4_TXBUFSIZE=1500
 CONFIG_UART5_IFLOWCONTROL=y
 CONFIG_UART5_OFLOWCONTROL=y
+CONFIG_UART5_RXBUFSIZE=800
 CONFIG_UART5_RXDMA=y
 CONFIG_UART5_TXBUFSIZE=10000
 CONFIG_UART5_TXDMA=y