Bought my first case & tempered glass from here:

https://forum.lowyat.net/index.php?act=ST&f...0#entry77283953

Good price and responsive seller.. I like the smartdevil tempered glass coz it comes with the tool to properly fit ur tempered glass on your own   

You could unlock unofficially but you have a chance of bricking it. Rotting with a unofficially unlocked bootloader is not recommended. In short, to be on safe side, always proceed the official unlock method.

http://en.miui.com/unlock/
Try to check here by clicking unlock now. Sometimes they might not send approval sms at all. You better off use the official method if you can't bear the risk of bricking phone. So far I'd never heard of flashing CM13 with unofficial unlock bootloader but if you willing to be the white rat, you could do so. 

I've been using the unofficial method for quite a while since the bootloader got relocked last time I tried to go back to miui rom.
Since i didn't wanna wait again for another month for unlock request, i just used unofficial method instead.
And be sure to use specific twrp based on your bootloader condition to avoid another relocked BL like mine

http://forum.xda-developers.com/redmi-note...-twrps-t3406708

http://en.miui.com/thread-253680-1-1.html

If you can download the tool after login, you have the approval.

For the second question, I'm not sure about that

Worse case scenario, you have to use test point method to revive your phone.

SuperSU control which app had root access.

did you flashed supersu in twrp at the first place?

then it's rooted.

there is unofficial way but you will need to replace the mbn file everytime you flash new miui rom..forgot to flash you will brick your phone

your phone will become brick aka paperweight. in other words, it wont boot

Test point method to unbrick it

Updating via updater is not recommended.

Unless you want to unlock officially, you don't really need to lock it back.

anyone here using stock cm13? just wondering if notification sound still come via speaker+headset when headset is used?

i guess that user wants to use apps that use safetynet like android pay & pokemon go since those don't work when su is mounted in the system

supposed you still..but have to re root later.

will brick if u forgot to replace the mbn files.

just disable auto update in updater.

any yes since you unlocked bootloader..you will need repeat the same thing on every miui update..

It will restart again, so you are wasting your effort to do so.