The quantum mechanics of black holes is still open, isn't it? As I recall even Hawking entropy depends on putting the (non-unitary) Second Law of Thermodynamics

The quantum mechanics of black holes is still open, isn't it? As I recall even Hawking entropy depends on putting the (non-unitary) Second Law of Thermodynamics in as a prior. This turns out to be consistent with (unitary) string theory and LQG, so far at least.