Hi bro, i tried also to update my W10 today but the same error appear to me.
Searching in YouTube, i found a comment with another command for this error, the command is this:
bootrec /nt60 sys
And after this, type the bootrec /fixboot command. With this, i tried to update but after spending 6 hours, nothing, the blue screen appear to me every minute. My only way to get again the PC start, reinstalling the system without deleting my documents and games, for my luck, but this delete your configurations and some apps installed on the system disc partition, like Microsoft Office apps and all Redistributables and DirectX tools. Now i am reinstalling every app and playing my games again, i hope my reply can help you, greetings from Paraguay and sorry for my bad english :P