Opportunity is on the west rim of Endeavour Crater heading towards 'Marathon Valley,' a putative location for abundant clay minerals only about a mile (about 1 kilometer) to the south.

Because of the deteriorating performance of the Flash file system, the project reformatted the rover's Flash memory on Sol 3862 (Dec. 4, 2014). Although the rover's operation improved immediately after the reformat, Flash behavior quickly deteriorated. Opportunity experienced a set of resets on Sols 3864 and 3865 (Dec. 6 and Dec. 7, 2014). After this, the project made the decision to operate the rover without the use of Flash memory until another fix can be implemented.

On Sol 3866 (Dec. 8, 2014), the rover was booted without using Flash (and instead storing data products in volatile RAM memory) and all the fault conditions were cleared.

On Sol 3867 (Dec. 9, 2014), Opportunity performed light science activities in preparation for driving on the next sol. Longer term, the project is developing a strategy to mask off the troubled sector of Flash and resume using the remainder of the Flash file system.

As of Sol 3867 (Dec. 9, 2014), the solar array energy production was 500 watt-hours, an atmospheric opacity (Tau) of 1.215 and a solar array dust factor of 0.659.

Total odometry is 25.66 miles (41.30) kilometers.