  The Schwarzschild black hole metric with mass $M$ has the limit of the
vanishing mass when one get the Minkowski space. We study behavior of the
entanglement entropy by using the island formula and the limit of the vanishing
black hole mass. The black hole information problem appears if one considers
the lowering its mass. It was noted recently that the formula derived for
eternal black holes leads to an increase of the entanglement entropy, which is
singular when $M \to 0$. In this process, it arises the other problem of the
Schwarzschild black hole explosion, as the black hole temperature blows up as
the mass vanishes.We show that it is possible to solve the entropy explosion
for small masses, if one admit the following bound: $c<AM$ where $c$ is central
charge of the Virasoro algebra, M is black hole mass and A is positive
constant. We are examining the possibilities of applying such a mechanism to
calculate entropy with and without an island. It was shown that applying the
mechanism of the dependence of the central charge on the black hole mass allows
us to obtain a similar Page curve without using an island.
