How do I flash a Radeon Sapphire Pulse RX580 Vid card to display MacPro 5.1 UEFI Boot screen?

Has anyone figured out how to flash a SAPPHIRE Radeon PULSE RX 580 8GB GDDR5 video card so that a MacPro 5.1 will display the Apple logo and startup progress bar and allow you to run options such as internet recovery or choose the startup disk boot options? I have a 2010 MacPro 5.1 and installed a SAPPHIRE Radeon PULSE RX 580 8GB GDDR5 video card which Apple recommends. However, when booting my MacPro 2010 with 5.1 firmware, I see nothing until it displays the log in screen. I have both High Sierra and Mojave installed because I still have 32 bit programs and Catalina won't support 32 bit programs. I read that MacVidCards supposedly claim that they can flash this video card so that the MacPro UEFI can be displayed on boot but I also read that this company has been known to ghost customers and unfortunately some never received their video cards back!

I have been a fan of both Apple and this site. Surly someone on here has figured out how to make this work? Any answers will be truly appreciated!

Thanks,

Clayton