Two-dimensional signal-to-noise spectra and sky spectra of the galaxies discussed in the text. Top: spectra of the i-band dropout GDS J033229.41-274537.8 observed in F18 (upper part) and B27 (lower part). The Lyα line is marked with a dotted circle. Bottom: stacked 52 h spectrum of the z-band dropout G2_1408 is shown with the individual spectra of F18, B27, and B7 (lower part). The expected position of the Lyα continuum break is marked with dotted horizontal lines (see text). In the B27 spectrum the redshift values are reported above the sky as a reference. In the F18 spectrum, the dotted circle marks the older (here revisited) feature discussed in Fontana et al. (2010). The B7 spectrum shows also the Hα emission from the secondary object J033242.32-274651.1 at z = 0.535, which is useful here as an example of a still performing FORS + 600z configuration beyond one micron.