diff --git a/platformio.ini b/platformio.ini
index 407928203..55c236899 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -32,6 +32,7 @@ build_flags =
   -D ARDUINOJSON_USE_DOUBLE=0
   -D ARDUINOTRACE_ENABLE=0
   -D CONFIG_ETH_ENABLED
+  -D CONFIG_UART_ISR_IN_IRAM
   -D CONFIG_ASYNC_TCP_STACK_SIZE=8192
 
 unbuild_flags =