I have this exact same problem. Surface pro 4 stuck on this "Secure boot off red line surface screen". I can't access the uefi menu no matter what I try or for how long. So far I've tried to force it to boot from the USB so that I could load a recovery image with no success.i created a bookable drive so that i could make changes via the drive itself as well with no success. I can't even tell if it's recognizing the usb at all. It just sits on this red bar screen doing nothing else. It doesn't make any noise, no flickers nothing. I'm at a loss of what to try because all of the microsoft support guides all point back to making changes in the Uefi menu. But if I can't ever access that menu obviously the guides are useless. I have been unsuccessful at finding any documentation or mention of it being possible for the uefi menu to have been eliminated and what to do if this was the case. I didn't see an answer to this inquiry, so I was hoping to make a new entry and get some attention to this thread, that way maybe someone has solved this and would be so kind as to share what it was that worked. Please and thank you in advance.