For accretion rates { \dot { M } } \sim 0.1 { M } _ { \odot } /s to a few solar mass black hole the inner part of the disk is expected to make a transition from advection dominance to neutrino cooling .
This transition is characterized by sharp changes of the disk properties .
I argue here that during this transition , a modest increase of the accretion rate leads to powerful enhancement of the Poynting luminosity of the GRB flow and decrease of its baryon loading .
These changes of the characteristics of the GRB flow translate into changing gamma-ray spectra from the photosphere of the flow .
The photospheric interpretation of the GRB emission explains the observed narrowing of GRB pulses with increasing photon energy and the luminosity-spectral peak relation within and among bursts .