  The Fermi observations of GRB 110721A (Axelsson et al. 2012) have revealed an
unusually high peak energy ~ 15 MeV in the first time bin of the prompt
emission. We find that an interpretation is unlikely in terms of internal shock
models, and confirm that a standard black-body photospheric model also falls
short. We show that dissipative photospheric synchrotron models ranging from
extreme magnetically dominated to baryon dominated dynamics, on the other hand,
are able to accommodate such high peak values.
