diff --git a/ports/stm32/machine_uart.c b/ports/stm32/machine_uart.c
index 0f139ae83272f..277ae67ef2c54 100644
--- a/ports/stm32/machine_uart.c
+++ b/ports/stm32/machine_uart.c
@@ -41,6 +41,7 @@
     { MP_ROM_QSTR(MP_QSTR_RTS), MP_ROM_INT(UART_HWCONTROL_RTS) }, \
     { MP_ROM_QSTR(MP_QSTR_CTS), MP_ROM_INT(UART_HWCONTROL_CTS) }, \
     { MP_ROM_QSTR(MP_QSTR_IRQ_RXIDLE), MP_ROM_INT(UART_FLAG_IDLE) }, \
+    { MP_ROM_QSTR(MP_QSTR_IRQ_RX), MP_ROM_INT(UART_FLAG_RXNE) }, \
 
 static void mp_machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
diff --git a/ports/stm32/uart.h b/ports/stm32/uart.h
index 956cbb044f6c0..de4b70cdea738 100644
--- a/ports/stm32/uart.h
+++ b/ports/stm32/uart.h
@@ -52,7 +52,7 @@ typedef enum {
 #define CHAR_WIDTH_9BIT (1)
 
 // OR-ed IRQ flags which are allowed to be used by the user
-#define MP_UART_ALLOWED_FLAGS UART_FLAG_IDLE
+#define MP_UART_ALLOWED_FLAGS (UART_FLAG_IDLE | UART_FLAG_RXNE)
 
 // OR-ed IRQ flags which should not be touched by the user
 #define MP_UART_RESERVED_FLAGS UART_FLAG_RXNE