Nobe,
I noticed on 2.8 that I got a black screen that seemed like forever. Eventually I could touch the screen and I would get an unlock to get into TWRP. I don't have that issue with 2.7.1.0. That may be what he is experiencing. I had to go back to 2.7.1.0.
Any fix for this Black Screen yet? I want to go up to 2.8 but that black screen is annoying.