git reset --hard 1258f0d0aae
But be careful, if the descendant commits between 1258f0d0aae and HEAD are not referenced in other branches it'll be tedious (but not impossible) to recover them, so you'd better to create a "backup" branch at current HEAD, checkout master, and reset to the commit you want.
Also, be sure that you don't have uncommitted changes before a reset --hard, they will be truly lost (no way to recover).
