We present an update to the photometric calibration of the COMBO-17 catalogue
on the Extended Chandra Deep Field South, which is now consistent with the
GaBoDS and MUSYC catalogues. As a result, photometric redshifts become slightly
more accurate, with <0.01 rms and little bias in the delta_z/(1+z) of galaxies
with R<21 and of QSOs with R<24. With increasing photon noise the rms of
galaxies reaches 0.02 for R<23 and 0.035 at R~23.5. Consequences for the
rest-frame colours of galaxies at z<1 are discussed.Comment: A&A research note, resubmitted 02 Oct 2008, 4 pages in print forma