After flashing TWRP and booting it (situation described in title), TWRP asks for password. When I bypass it, TWRP cannot mount anything. When I reboot to system, it is stuck at the startup animation forever. Only can boot when I reflash stock recovery. Actually I have to reflash system too, it cannot boot otherwise.
I also tried boot.img replacement by Chainfire, result is exactly the same.
Has anybody successfully rooted Android 6 at all? What was the procedure?
Update Just installed apk for supersu 2.51 (beta) and it seems to work - at least adb now goes root (could not before). However twrp still asks for password and cannot mount anything.