diff --git a/include.rst b/include.rst
index ded950e..917558f 100644
--- a/include.rst
+++ b/include.rst
@@ -1,3 +1,9 @@
+.. |br| raw:: html
+
+   <br />&nbsp;
+.. |vel| unicode:: 0x22EE
+   :trim:
+
 .. |cartridge| image:: /usage/images/cartridge.png
 .. |cartridge_small| image:: /usage/images/cartridge_small.png
 .. |cassette| image:: /usage/images/cassette.png
diff --git a/settings/hdd.rst b/settings/hdd.rst
index cfbcc51..b15fbdb 100644
--- a/settings/hdd.rst
+++ b/settings/hdd.rst
@@ -5,12 +5,6 @@
 
 The *Hard disks* page contains settings related to the emulated machine's fixed disks.
 
-.. |br| raw:: html
-
-   <br />&nbsp;
-.. |vel| unicode:: 0x22EE
-   :trim:
-
 Hard disk list
 --------------
 
@@ -87,6 +81,8 @@ The *New...* button opens a new window allowing you to create an existing hard d
 
    * On MFM/RLL, XTA and ESDI disks, the second number is 0 for the first drive on the controller, and 1 for the second drive.
 
+.. note:: If the disk is attached to a channel or controller that doesn't exist, such as the tertiary IDE channel with no tertiary IDE controller present, it will be effectively disabled.
+
 Press the *OK* button to create the disk image file, or *Cancel* to close the window.
 
 Adding an existing disk