ImageAssist- BIOS Setting for Dell-XPS-15 (9575)

Hello Team, I have been using Image Assist for Dell desktops and laptops on following models. We recently purchased couple of Dell XPS-15_9575. I have been trying to change the BIOS setting but its not working. XPS-15 model comes with SSD. Can someone send me the detailed step by step instruction or guide me what to do. I tried couple of options but its failing and if I try couple of times the OS crashed and I have to go back to Factory setting. thanks Ned