[install-guide/f21-branch: 22/32] Clarifications in Booting the Installer

[pbokoc]

commit a68d67b5a0743bc8d203f9c01d2b5687a032e34e
Author: Petr Bokoc <pbokoc at redhat.com>
Date:   Mon Dec 8 22:32:57 2014 +0100

    Clarifications in Booting the Installer

 en-US/Booting_the_Installation.xml |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/en-US/Booting_the_Installation.xml b/en-US/Booting_the_Installation.xml
index a067a23..cf2973e 100644
--- a/en-US/Booting_the_Installation.xml
+++ b/en-US/Booting_the_Installation.xml
@@ -83,6 +83,14 @@ Press F12 to select boot device, or Del to enter SETUP
         <para>
             Every menu entry in the list is a predefined set of boot options, and these options can be customized to change some aspects of the installer's behavior. To edit the default set of boot options, press <keycap>Tab</keycap> on BIOS systems, or <keycap>e</keycap> on UEFI systems. The key to use is also displayed at the bottom of the screen.
         </para>
+        <note>
+            <para>
+                Editing boot options in <application>GRUB2</application> (on UEFI systems) will display the entire configuration for the selected entry. Actual boot options are configured on the line which starts with the <literal>linux</literal> (or <literal>linux16</literal> or <literal>linuxefi</literal>) keyword. Do not modify any other lines in the configuration.
+            </para>
+            <para>
+                On systems with BIOS firmware, only the actual boot options are displayed when you press <keycap>Tab</keycap>.
+            </para>
+        </note>
         <para>
             When editing the default set of options, you can change the existing ones as well as append additional ones. Once you finish, press <keycap>Enter</keycap> on BIOS or <keycombo><keycap>Ctrl</keycap><keycap>X</keycap></keycombo> on UEFI to boot the installer using your customized options.
         </para>