As an unsupported option, you can use @zzzhouuu 's driver sysext which was set to use the non-free firmware, and still supports your card (but won’t have any 50-series or beyond support)
As an unsupported option, you can use @zzzhouuu 's driver sysext which was set to use the non-free firmware, and still supports your card (but won’t have any 50-series or beyond support)