diff --git a/libraries/AP_HAL_ChibiOS/hwdef/fmuv3/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/fmuv3/hwdef.dat
index 43a8be3ee9..d41706be35 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/fmuv3/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/fmuv3/hwdef.dat
@@ -478,3 +478,7 @@ define HAL_I2C_MAX_CLOCK 100000
 # define CH_DBG_SYSTEM_STATE_CHECK TRUE
 # define CH_DBG_ENABLE_STACK_CHECK TRUE
 
+# we can't share IO UART (USART6)
+DMA_NOSHARE USART6_TX USART6_RX
+DMA_PRIORITY USART6* TIM* SPI*
+