Secure boot -_-. I can't install Linux from live USB boot. And I can't switch off this secure boot...

Ubuntu an many other support secure boot installation I believe. It requires GPT formatted installer medium though. Which device BTW?

I know how you feel (I own a baytrail device).
There is a signed version of GRUB2. There were also some secure boot keys leaked a while ago which might be useful if you need something other than grub.

Can I clear secure boot key ?

@Johngtrs yes. On some machines you also need to switch its mode from Windows to Other OS.

@OMGtechy ty. but this will remove my current Windows 10 ?

Move the clear CMOS jumper?

@Johngtrs yup. You need to reinstall windows. AFAIK windows doesn't play nice if you disable secure boot. Add the "shim-signed" package on your installation and rebuild grub. That may work.

@Johngtrs nope, it'll just allow other operating systems :)

@flag0 Said to reinstall windows and @OMGTechy Said no. What i supposed to do ? :p

@Johngtrs I had no problem switching from efi to legacy with my installed windows. The startup looks different (well... more legacy), but windows had no problems. Disabling secure boot didn't have problems, too. Save your data and give it a try. (save your windows key, too)

Try this

https://rol.im/securegoldenkeyboot/

It has a dumb intro, so wait like 15 seconds