putting these file on your box you will be able to start when your box boots choosing the image you want

about buttons...following Tideglo's choices(he is the enigma2 developer for sifteam images on ipbox hd) you can:

-pressing 1 =NFS
-pressing 2= USB (without internal hd /dev/sda1)
-pressing 3= USB (with internal hd /dev/sda1)
-pressing 4=Flash

at the next reboot you have only press the button to change images

How install them:

-rename the file for your box in usb_update.img-send and install it following the usb modality

the next firmware will have already it inside