Normalised HIRES spectrum of GRB 080810 (black) around the Lyman limit of 911.8 Å. Fits to the absorption by H i by the four systems of the host are plotted as dashed lines in red, orange, cyan, and dark blue for systems A–D, respectively, with the combined fit shown in solid green. Labels show the location of each order for each component. The error spectrum is shown in grey. The thick red line corresponds to the upper limit in system A of N_{H i} ≤ 16.9.