The Flash software is included with the adaptor plans.
Really, though, the odds of this working are zero or less. The 1.4 ROMs depend on the SCSI controller found in the A3000, the 68030's MMU, and various addressing schemes. Maybe, MAYBE you could get this to work with an A2000, 2630 board, and 2091 SCSI controller, but don't count on it.
Besides, you can only Kick in 1.3, 2.04, or a beta version of 3.1 (and not very cleanly, either) with the 1.4 chips. Might as well just do that with the Flash board.