[regularfry]

It doesn't have to stall to stand still. Or squat, at least. With that leg layout it can safely rest against its backstops when the motors switch off. The drive motors, anyway. The hip motors probably still need to hold vertical balance, but that's intermittent, not a stall load.

[regularfry]

Oh, just thought in addition to this: you could define a standing locked position, too, if you drive the capstans to full rotation inwards so the knees only just reverse, and put extra backstops there. Not sure what that would do on uneven ground, I think you'd need to balance centrally over three legs and let the fourth hang loose.