A hybrid fill mode has been tested at the Photon Factory storage ring (PF-ring). Since a bunch-by-bunch feedback system was not available because of the high contrast of currents between the bunch train and the single bunch, we suppressed multibunch instabilities in the transverse and longitudinal planes by using the octupole magnets and RF phase modulation, respectively. We also suppressed single-bunch instabilities by controlling ring chromaticity. As a result, we successfully stored a 450 mA current with the hybrid fill mode: 1/2 filling (400 mA: 2.56 mA/bunch × 156) + 1 single bunch opposite to the bunch train (50 mA/bunch). Although there were three technical problems to be solved for the user operation, we have already obtained possible solutions to them.