  GRB 980425 and GRB 031203 are apparently two outliers with respect to the
correlation between the isotropic equivalent energy E_iso emitted in the prompt
radiation phase and the peak frequency E_peak of the spectrum in a vF(v)
representation (the so-called Amati relation). We discuss if these two bursts
are really different from the others or if their location in the E_iso-E_peak
plane is the result of other effects, such as viewing them off-axis, or through
a scattering screen, or a misinterpretation of their spectral properties. The
latter case seems particularly interesting after GRB 060218, that, unlike GRB
031203 and GRB 980425, had a prompt emission detected both in hard and soft
X-rays which lasted ~2800 seconds. This allowed to determine its E_peak and
total emitted energy. Although it shares with GRB 031203 the total energetics,
it is not an outlier with respect to the Amati correlation. We then investigate
if a hard-to-soft spectral evolution in GRB 031203 and GRB 980425, consistent
with all the observed properties, can give rise to a time integrated spectrum
with an E_peak consistent with the Amati relation.
