Knowing Toshiba, there's not much of a chance for a firmware update.
If Toshiba doesn't have an update available (most likely) and you really want a RPC1 drive then you'll have to crossflash your drive. I would suggest using the latest Lenovo firmware (LE12) which is the newest firmware available for GT30N drives (see the LG firmware announcement thread: viewtopic.php?f=2&t=42502
). You can patch the firmware using MCSE, which supports this firmware (just load the firmware in MCSE and follow the instructions).
I have crossflashed a GT30N drive (not a Toshiba OEM one, but it should not really matter) to the Lenovo LE10 firmware before without problems, and I have just updated the crossflashed drive to LE12 and I can confirm that MCSE can still patch this firmware to RPC1.
Since there's no Toshiba firmware available, if you're not happy with the crossflash from whatever reason or if something goes wrong, you won't be able to go back to your original Toshiba firmware (since currently there are no tools available to dump the firmware from these drives), so bare that in mind if you decide to go ahead with the crossflash. There's always a small risk involved with crossflashing, but as I said these drives have been crossflashed before so I see no reason why it should not be working just fine for you too... On the plus side, not only that you'll have a RPC1 drive, but you'll also have a newer firmware dated 01.12.2010 (as opposite to your current one dated 02.03.2010).