  A recent understanding on how quantum effects may affect black-hole evolution
opens new scenarios for dark matter, in connection with the presence of black
holes in the very early universe. Quantum fluctuations of the geometry allow
for black holes to decay into white holes via a tunnelling. This process yields
to an explosion and possibly to a long remnant phase, that cures the
information paradox. Primordial black holes undergoing this evolution
constitute a peculiar kind of decaying dark matter, whose lifetime depends on
their mass $M$ and can be as short as $M^2$. As smaller black holes explode
earlier, the resulting signal have a peculiar fluence-distance relation. I
discuss the different emission channels that can be expected from the explosion
(sub-millimetre, radio, TeV) and their detection challenges. In particular, one
of these channels produces an observed wavelength that scales with the redshift
following a unique flattened wavelength-distance function, leaving a signature
also in the resulting diffuse emission. I conclude presenting the first
insights on the cosmological constraints, concerning both the explosive phase
and the subsequent remnant phase.
