   <p class="mac">Immediately press-and-hold the
   <span class="keycap">Option</span> key (<span class="keycap">Alt</span> key) until a list of possible startup
   disks appears.</p>

   [[!img install/inc/screenshots/mac_option_key.png class="screenshot mac" link="no" alt="'Option' or 'alt' key in the bottom left of Mac keyboard"]]

   <p class="mac">Choose the USB stick and press
   <span class="keycap">Enter</span>. The USB stick appears as an external hard
   disk and might be labelled <span class="guilabel">EFI Boot</span> or
   <span class="guilabel">Windows</span> like in the following screenshot:</p>

   [[!img install/inc/screenshots/mac_startup_usb.png class="screenshot mac" link="no" alt="Screen with the logo of an internal hard disk labelled 'Macintosh HD' and an external hard disk labelled 'Windows' (selected)"]]
