  The black hole firewall conjecture is based on Page curve hypothesis, which
claims that entanglement between black hole and Hawking radiation is almost
maximum. The hypothesis is inspired by Lubkin-Lloyd-Pagels-Page theorem for
degenerate systems with zero Hamiltonian. Adopting canonical typicality for
nondegenerate systems with nonvanishing Hamiltonians, the entanglement becomes
nonmaximal,and energetic singularities (firewalls) do not emerge for general
systems. For static thermal pure states of black hole and Hawking radiation,
entanglement entropy equals thermal entropy of the smaller system.
