diff --git a/nuttx-configs/px4fmu-v2/nsh/defconfig b/nuttx-configs/px4fmu-v2/nsh/defconfig
index e828e42be0..59abc22fb6 100644
--- a/nuttx-configs/px4fmu-v2/nsh/defconfig
+++ b/nuttx-configs/px4fmu-v2/nsh/defconfig
@@ -564,7 +564,7 @@ CONFIG_USART1_2STOP=0
 # USART2 Configuration
 #
 CONFIG_USART2_RXBUFSIZE=600
-CONFIG_USART2_TXBUFSIZE=1860
+CONFIG_USART2_TXBUFSIZE=1100
 CONFIG_USART2_BAUD=57600
 CONFIG_USART2_BITS=8
 CONFIG_USART2_PARITY=0
@@ -575,8 +575,8 @@ CONFIG_USART2_OFLOWCONTROL=y
 #
 # USART3 Configuration
 #
-CONFIG_USART3_RXBUFSIZE=400
-CONFIG_USART3_TXBUFSIZE=400
+CONFIG_USART3_RXBUFSIZE=300
+CONFIG_USART3_TXBUFSIZE=300
 CONFIG_USART3_BAUD=57600
 CONFIG_USART3_BITS=8
 CONFIG_USART3_PARITY=0
@@ -587,8 +587,8 @@ CONFIG_USART3_OFLOWCONTROL=y
 #
 # UART4 Configuration
 #
-CONFIG_UART4_RXBUFSIZE=400
-CONFIG_UART4_TXBUFSIZE=400
+CONFIG_UART4_RXBUFSIZE=300
+CONFIG_UART4_TXBUFSIZE=300
 CONFIG_UART4_BAUD=57600
 CONFIG_UART4_BITS=8
 CONFIG_UART4_PARITY=0
@@ -599,8 +599,8 @@ CONFIG_UART4_2STOP=0
 #
 # USART6 Configuration
 #
-CONFIG_USART6_RXBUFSIZE=400
-CONFIG_USART6_TXBUFSIZE=400
+CONFIG_USART6_RXBUFSIZE=300
+CONFIG_USART6_TXBUFSIZE=300
 CONFIG_USART6_BAUD=57600
 CONFIG_USART6_BITS=8
 CONFIG_USART6_PARITY=0
@@ -611,8 +611,8 @@ CONFIG_USART6_2STOP=0
 #
 # UART7 Configuration
 #
-CONFIG_UART7_RXBUFSIZE=400
-CONFIG_UART7_TXBUFSIZE=400
+CONFIG_UART7_RXBUFSIZE=300
+CONFIG_UART7_TXBUFSIZE=300
 CONFIG_UART7_BAUD=57600
 CONFIG_UART7_BITS=8
 CONFIG_UART7_PARITY=0
@@ -623,8 +623,8 @@ CONFIG_UART7_2STOP=0
 #
 # UART8 Configuration
 #
-CONFIG_UART8_RXBUFSIZE=400
-CONFIG_UART8_TXBUFSIZE=400
+CONFIG_UART8_RXBUFSIZE=300
+CONFIG_UART8_TXBUFSIZE=300
 CONFIG_UART8_BAUD=57600
 CONFIG_UART8_BITS=8
 CONFIG_UART8_PARITY=0
@@ -667,7 +667,7 @@ CONFIG_CDCACM_NWRREQS=4
 CONFIG_CDCACM_NRDREQS=4
 CONFIG_CDCACM_BULKIN_REQLEN=96
 CONFIG_CDCACM_RXBUFSIZE=600
-CONFIG_CDCACM_TXBUFSIZE=5000
+CONFIG_CDCACM_TXBUFSIZE=4000
 CONFIG_CDCACM_VENDORID=0x26ac
 CONFIG_CDCACM_PRODUCTID=0x0011
 CONFIG_CDCACM_VENDORSTR="3D Robotics"