Don't use 290 version, use 534.
There's a lot bricked device reported when guys flashed 290 over 757 and version before 757 (can't remember number of that version).
Also, if you don't plan to unlock bootloader there's no need to backup TA, it's OK to do that but it's not necessary.
You can't lose DRM keys as long as you don't unlock it.
And yeah...use binary root method (just Google "binary root method xda" and pick first result.
360 and Kingo are banned from XDA because they read and store your IMEI (and that's totally unnecessary)
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