Another option that I know Mikl and I have both used is to get a long drill bit and put a metal rod through the flake and the rock behind as reinforcing. Obviously you're going to have to make a judgement as to whether that's going to be effective in any particular case.
My preferred option if it's not going to be too much of a scar or hazard is to get rid of loose stuff. A small prybar so you can pull something out without being in the line of fire is OK. A car jack is probably an admission that something isn't really that loose.