Light-curves corresponding to reverse and forward shock emission assuming the ejecta responsible for the prompt emission is followed by slower moving outflow with Γ_s = 20, Ė_s = 2 × 10⁴⁹ erg s^-1 and lasting 6000 s, which makes the plateau. The tail of this material is characterized by the same Ė, lasting 400 s and with a declining Lorentz factor from Γ ≈ 20 down to Γ ≈ 1 with Γ(t_inj) ∝ (t_f−t_inj)^2/11. The reverse shock crossing this material accounts for a bump in the afterglow data. The time of the bump and the flux levels during and after the bump match the observed levels. We assume here A_∗ = 2.2,ϵ_e,f = 0.1,ϵ_B,f = 2.5 × 10^-5,ϵ_e,r = 0.1,ϵ_B,r = 4 × 10^-3,p = 2.15. The top panels correspond to the 1 keV light curve and the bottom panels correspond to the 1 eV light curve. Left: light curve for the reverse shock (blue dot-dashed line) and forward shock (red dashed line). A yellow solid line depicts the sum of the reverse and forward shock contributions. Right: the plots show the evolution of ν_c,R (blue circles), ν_m,R (red pluses), ν_c,f (yellow dashed line) and ν_m,f (purple dot-dashed line). The observed frequency is depicted by a horizontal line.