diff --git a/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig b/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig
index 81a4dce6c5..384726875d 100644
--- a/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig
+++ b/boards/ark/fmu-v6x/nuttx-config/nsh/defconfig
@@ -291,7 +291,6 @@ CONFIG_UART4_RXBUFSIZE=600
 CONFIG_UART4_TXBUFSIZE=1500
 CONFIG_UART5_IFLOWCONTROL=y
 CONFIG_UART5_OFLOWCONTROL=y
-CONFIG_UART7_RXBUFSIZE=1500
 CONFIG_UART5_RXDMA=y
 CONFIG_UART5_TXBUFSIZE=10000
 CONFIG_UART5_TXDMA=y
diff --git a/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig b/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
index 21db79889c..13191fc716 100644
--- a/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
+++ b/boards/px4/fmu-v6x/nuttx-config/nsh/defconfig
@@ -291,7 +291,6 @@ CONFIG_UART4_RXBUFSIZE=600
 CONFIG_UART4_TXBUFSIZE=1500
 CONFIG_UART5_IFLOWCONTROL=y
 CONFIG_UART5_OFLOWCONTROL=y
-CONFIG_UART7_RXBUFSIZE=1500
 CONFIG_UART5_RXDMA=y
 CONFIG_UART5_TXBUFSIZE=10000
 CONFIG_UART5_TXDMA=y