Unable to boot on Debian Live CD on my HP Laptop - "Selected boot image did not authenticate"

I'm trying to boot from a Debian Live CD (the debian-8.5.0-amd64-DVD-1.iso available here: http://cdimage.debian.org/debian-cd/8.5.0/amd64/bt-dvd/).

It doesn't work when I just let the computer start (the boot order is correct and worked for Ubuntu Mate Live CD).

I'm getting the following error message when I try to boot from the BIOS menu : Selected boot image did not authenticate.

I read on HP forum that I should enable Legacy Boot Mode and disable Secure Boot. I did that, but each time I go back to the BIOS menu, the Legacy Boot Mode is disabled again and the Secure Boot is enabled again (though I correctly used "Save & Exit").

I'm a bit at loss, any help? I'm using an HP Pavilion.

I had the same problem while trying to install Debian Jessie from USB on my new HP laptop that came with Windows 10. I fixed it by disabling Secure Boot and enabling Legacy Boot Mode in the BIOS and saving just as you did.

However, upon reboot I got a message saying "There is a boot mode change pending, press Esc if you do not want these changes to take effect or type in the given password+Enter to apply the changes"

Please note that repeatedly pressing Esc may cancel that prompt and prevent Legacy mode from being implemented so be patient, I had to do that twice before I could get it. After that everything worked out smoothly