2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/178003We discuss a previous attempt at a microscopic counting of the entropy of asymptotically flat non-extremal black-holes. This method used string dualities to relate 4 and 5 dimensional black holes to the BTZ black hole. We show how the dualities can be justified in a certain limit, equivalent to a near horizon limit, but the resulting spacetime is no longer asymptotically flat.10 pages, harvmac. v(2) typo correctedHigh Energy Physics - Theorytext