diff --git a/static/install/cli.html b/static/install/cli.html
index 9a398258..89734df2 100644
--- a/static/install/cli.html
+++ b/static/install/cli.html
@@ -333,6 +333,11 @@ Installed as /home/username/platform-tools/fastboot</pre>
                 <p>Alternatively, turn off the device, then boot it up while holding the volume
                 down button during the boot process. You can either boot it with the power button
                 or by plugging it in as required in the next section.</p>
+
+                <p>This step is not complete until your device displays a red warning triangle
+                and the words "Fastboot Mode".  You must not press the device's power button
+                to activate the "Start" menu item, because the device must remain paused in
+                Fastboot mode for the <code>fastboot</code> command to connect to it.</p>
             </section>
 
             <section id="connecting-device">
diff --git a/static/install/web.html b/static/install/web.html
index 99123ea6..bdc4873b 100644
--- a/static/install/web.html
+++ b/static/install/web.html
@@ -225,6 +225,11 @@
                 <p>Alternatively, turn off the device, then boot it up while holding the volume
                 down button during the boot process. You can either boot it with the power button
                 or by plugging it in as required in the next section.</p>
+
+                <p>This step is not complete until your device displays a red warning triangle
+                and the words "Fastboot Mode".  You must not press the device's power button
+                to activate the "Start" menu item, because the device must remain paused in
+                Fastboot mode for the installer to connect to it.</p>
             </section>
 
             <section id="connecting-device">