I had problems with printing on a HP PSC 1315, because I couldnīt find any driver (neither GIMP). It works with Olegs firmware and HPIJS driver and ESP Ghostscript (more info here:
Mac OSX 10.3 Panther and 10.4 Tiger
* Original router firmware
Does not work wih original firmware and standard OSX drivers. No further testing with original firmware
* Firmware by Oleg
Does not work with OSX standard drivers.
Works with downloaded HPIJS driver and ESP Ghostscript (see link HPIJS). Printed via LAN connection with other router, connected with ASUS and WIFI connection with ASUS.
Choose IP Printig, Socket/HP Jet direct, IP Adress Router, Model: HP PSC 1310 Foomatic/hpijs. LPR printing works also with this driver, but is slower. HPLIP driver not tested