OSDev.org

Good evening. How can I write directly to the UEFI Simple Text Output Protocol? I haven't been able to find any resources that explain this in a simple or straightforward way.

First you get a pointer to an EFI Simple Text Output Protocol. If you don't know where to get one of those, you probably want to use ConOut from the EFI System Table. The EFI Simple Text Output Protocol is (a pointer to) a struct that contains a function pointer named OutputString(). Call that function, passing the pointer to the EFI Simple Text Output Protocol (ConOut) as the first argument and your string as the second argument.

I have never used the Simple Text Protocol before. Is that even implemented in real world EFI implementations? Because I cannot imagine that Windows needs it to boot (and if Windows doesn't need it, I figure most vendors aren't gonna bother).

thanks!