Yes, the entire 2800 series (2811, 2821, 2851, 2801) uses this unified image.
This is the feature license for the 2800 series. It includes: C2800nm-adventerprisek9-mz.151-4.m12a.bin Download
Leave a comment below (on your blog) or check the Cisco Community forums for support on IOS 15.1(4)M12a specific features. Yes, the entire 2800 series (2811, 2821, 2851,