Hi Jason,
Just a quick note. Did you put whole coreboot to some high memory (the TEXT_BASE or whatever it has name for it - and reserve that memory)? If so, then must be just checked if coreboot changed some low memory. You can check it with the memory poison technique, check the previous mail. Maybe no other backups will be needed? Maybe the S4 resume from windows does not work because of some related memory corruption.
Rudolf