So I've been following this guide to get back to 100% stock ready to send my phone off for repair.
I'm so close! The rom is back to stock from running the RUU, my bootloader is set back to LOCKED, now all I need to to change S-OFF back to S-ON. The problem is that fastboot won't let me for some reason. I run the command fastboot oem writesecureflag 3 and this is the output I get
... (bootloader) partition hboot signature error (bootloader) writesecureflag: partitions siganture failed OKAY [ 1.048s]