diff --git a/docs/Config_Reference.md b/docs/Config_Reference.md
index 8d58e562..9d720d3c 100644
--- a/docs/Config_Reference.md
+++ b/docs/Config_Reference.md
@@ -4199,6 +4199,13 @@ SPI bus.
 The following parameters are generally available for devices using an
 I2C bus.
 
+Note that Klipper's current micro-controller support for i2c is
+generally not tolerant to line noise. Unexpected errors on the i2c
+wires may result in Klipper raising a run-time error. Klipper's
+support for error recovery varies between each micro-controller type.
+It is generally recommended to only use i2c devices that are on the
+same printed circuit board as the micro-controller.
+
 ```
 #i2c_address:
 #   The i2c address of the device. This must specified as a decimal
@@ -4212,6 +4219,7 @@ I2C bus.
 #   the type of micro-controller.
 #i2c_speed:
 #   The I2C speed (in Hz) to use when communicating with the device.
-#   On some micro-controllers changing this value has no effect. The
-#   default is 100000.
+#   The Klipper implementation on most micro-controllers is hard-coded
+#   to 100000 and changing this value has no effect. The default is
+#   100000.
 ```