This is my post on Whirlpool. I and others have found this method the best solution. https://forums.whirlpool.net.au/forum-replies.cfm?t=2249322&p=14
"On SM-G900I with 6.0.1 stock, I couldn't get CF-Auto -root to finish booting by auto or manual. So flashed TWRP with latest Odin then flashed...