Submodules and rewind

I am beginning to think sub-modules in git are as fragile and error prone as master documents in Microsuck word.

Because of a bone headed merge, I had to rewind one project back to a known good state, but the sub module stuff is now wedged and brain stuck on the old commit id.

Isn't there some simple way to do 'git sub-module remove' followed by 'git sub-module add' to reset the internal index?