docs/esp8266/quickref: Add note that machine.RTC is not fully supported.
See issues and
@@ -249,6 +249,10 @@ See :ref:`machine.RTC <machine.RTC>` ::
ntptime.settime() # set the rtc datetime from the remote server
rtc.datetime() # get the date and time in UTC
+.. note:: Not all methods are implemented: `RTC.now()`, `RTC.irq(handler=*) <RTC.irq>`
+ (using a custom handler), `RTC.init()` and `RTC.deinit()` are
+ currently not supported.
+
Deep-sleep mode
---------------
