Finally got my hands on a GTX 1080, put my RX 580 back in an eGPU rig. The card is working great in both MacOS and Windows on my 2012 12c. I occasionally boot over to Win to play some Star Wars Battlefront etc. Unfortunately, when I originally installed HS it converted my SSD to APFS. So without boot screen I can't easily return to MacOS because BC doesn't understand the APFS drive. I've tried option-boot guessing, and have had no success. When my RX 580 was installed, I just reset PRAM to get back to Mac OS. Kind of a lazy workaround. Obviously if I do that now, my web driver switches back to OS default. Easy enough to remote into.... Just curious if anyone has found a better solution? I'm considering wiping the drive and returning it to HFS for the software boot ability. Is that my best course of action?