  We study the doubly charged Callan-Giddings-Harvey-Strominger (CGHS) model,
which has black hole solutions that were found to be U-dual to the D1-D5-KK
black holes of the IIB supergravity. We derive the action of the model via a
spontaneous compactification on S^3 of the IIB supergravity on S^1*T^4 and
obtain the general static solutions including black holes corresponding to
certain non-asymptotically flat black holes in the IIB supergravity.
Thermodynamics of them is established by computing the entropy, temperature,
chemical potentials, and mass in the two-dimensional setup, and the first law
of thermodynamics is explicitly verified. The entropy is in precise agreement
with that of the D1-D5-KK black holes, and the mass turns out to be consistent
with the infinite Lorentz boost along the M theory circle that is a part of the
aforementioned U-dual chain.
