I'm dealing with a similar problem, except on 4 week sprints. It's not management, who doesn't care, it's the team itself which continues to be FIXATED on a burn down chart, to the extent that they massage story points, avoid doing work late in sprints, and are way too concerned with burndown in general.

Shipping valuable features without regressions is my metric of success. Not y=mx+b applied to story points.

Burn down charts are misused far too much to be considered generally valuable.