TWRP 2.8.7.0 asks for password on Marshmallow (Nexus 9), cannot mount anything 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.
Worked for me like this:


Boot into Fastboot
Flash Chainfire's WIP boot.img
Flash TWRP
Copy latest SuperSU BETA onto a USB stick
Use an OTG adapter to connect that USB stick to your Nexus 9
Boot into TWRP
Tap "Cancel" at the password prompt
Mount the USB stick
Install the SuperSU.zip from USB
Reboot


I didn't have to install stock recovery or anything else. It booted up just fine with all data still there.