diff --git a/config/example-extras.cfg b/config/example-extras.cfg
index fee9061aa..a75f8b10b 100644
--- a/config/example-extras.cfg
+++ b/config/example-extras.cfg
@@ -946,9 +946,10 @@
 #   I2C address used by this expander. Depending on the hardware jumpers
 #   this is one out of the following addresses: 62 63 112 113. This
 #   parameter must be provided.
-#i2c_bus: 0
-#   If the I2C implementation of your microcontroller supports multiple I2C
-#   busses, you may specify the bus number here. The default is 0.
+#i2c_bus:
+#   If the I2C implementation of your microcontroller supports
+#   multiple I2C busses, you may specify the bus name here. The
+#   default is to use the default micro-controller i2c bus.
 
 
 # Configure a TMC2130 stepper motor driver via SPI bus. To use this
@@ -1084,7 +1085,7 @@
 #   Select the SPI bus the TMC2660 stepper driver is connected to.
 #   This depends on the physical connections on your board, as well as
 #   the SPI implementation of your particular micro-controller. The
-#   default is bus 0.
+#   default is to use the default micro-controller spi bus.
 #spi_speed: 4000000
 #   SPI bus frequency used to communicate with the TMC2660 stepper
 #   driver. The default is 4000000.
diff --git a/docs/Config_Changes.md b/docs/Config_Changes.md
index 3b8db9096..2941c2b92 100644
--- a/docs/Config_Changes.md
+++ b/docs/Config_Changes.md
@@ -6,6 +6,9 @@ All dates in this document are approximate.
 
 # Changes
 
+20190404: The i2c_bus and spi_bus parameters (in various config
+sections) now take a bus name instead of a number.
+
 20190404: The sx1509 config parameters have changed. The 'address'
 parameter is now 'i2c_address' and it must be specified as a decimal
 number. Where 0x3E was previously used, specify 62.