there is.... in theory.
no clue what firmwares it's able to fudge or not... Anyways, you need to buy a certain type of usb dongle which utilizes LV2diag to force downgrade
it's expensive, unreliable and basically... don't do it.

anyways, the master keys have nothing to do with it since there kirk's key , while being master key, is just one of many. Without all of them it makes no difference if you have one or 10 of them.