diff --git a/docs/library/bluetooth.rst b/docs/library/bluetooth.rst
index 251ff399eca..22f1e9e24ea 100644
--- a/docs/library/bluetooth.rst
+++ b/docs/library/bluetooth.rst
@@ -39,6 +39,13 @@ Configuration
 
     The radio must be made active before using any other methods on this class.
 
+.. note:: On ESP32 the BLE interface will not operate correctly and will
+    probably lock up the board if the system clock frequency has been changed to
+    a value below 80MHz.  Whilst this limitation may have been lifted from more
+    recent members of the ESP32 product line, for compatibility reasons across
+    hardware variants it is suggested to keep the system clock frequency above
+    80MHz if you use the BLE interface.
+
 .. method:: BLE.config('param', /)
             BLE.config(*, param=value, ...)
 
diff --git a/docs/library/network.WLAN.rst b/docs/library/network.WLAN.rst
index 4e60d918125..5a3aecb7925 100644
--- a/docs/library/network.WLAN.rst
+++ b/docs/library/network.WLAN.rst
@@ -30,7 +30,14 @@ Methods
 
     Activate ("up") or deactivate ("down") network interface, if boolean
     argument is passed. Otherwise, query current state if no argument is
-    provided. Most other methods require active interface.
+    provided. Most other methods require the interface being active.
+
+.. note:: On ESP32 the WLAN interface will not operate correctly and will
+    probably lock up the board if the system clock frequency has been changed to
+    a value below 80MHz.  Whilst this limitation may have been lifted from more
+    recent members of the ESP32 product line, for compatibility reasons across
+    hardware variants it is suggested to keep the system clock frequency above
+    80MHz if you use the WLAN interface.
 
 .. method:: WLAN.connect(ssid=None, key=None, *, bssid=None)