is it possible to debrand a rm 877 lumia at&t 1020? i remember triying for some time to do this in the past but gave up after trying a couple of rom's. All failed verification or something like this, the program didn't allow them to be flashed.
i also used the guide in the link.
Xperia Z Ultra
Surface Pro 2
Doing Phone/Laptop hardware modding for some years. Seen a lot of broken things in my life.