Apart from when I selected recovery mode, an android robot lying on the floor with an error message. Then I press and hold power button and quickly press volume up button to enter recovery mode. There is no update from sdcard option only update from adb sideload option.
OnePlus CEO Carl Pei unveiled the Android 6.0 Marshmallow update plans for the OnePlus One, OnePlus 2 and OnePlus X in November 2015 in the official OnePlus forum. According to the post, the OnePlus one should receive the marshmallow update (in the form of the Cyanogen OS 13) in the first quarter of 2016. Only after that update, will Oxygen OS be adapted for Android Marshmallow. 2b1af7f3a8