Your drive is an HP OEM flavour, and the RF03 is the only available firmware for this OEM model.
The GH80N is a Renesas chipset drive which according to the SATA Integrators list seems to be the equivalent of the following drives: GH24NS70, GH22NS70, GH70N, GH16NS80, GHA2N.
The drive uses a GH82L core, while the GH70N family of drives use a GH72L core, so a simple crossflash is not possible. That is not to say that a crossflash is impossible, just that it is more complicated to do.
We know that the GH24NS70 for example uses the RENESAS R8J32060FP2 chipset. Although the SATA Integrators list is very likely correct, if you're prepared to be more adventurous and go for the more complicated crossflash method, it would be a good idea to open up the drive and double check first that it is indeed based on the same chipset. You might even find some GH70N references inside on the PCB if lucky.
The step by step crossflashing process which involves crossflashing the core as well, is described here: http://forum.rpc1.org/viewtopic.php?f=2&t=46780