Command-Option-P-R works with a wireless keyboard wired with the lightning cable (the one coming with the iMac Pro); however do not shutdown the Mac first.
Boot the Mac, restart it. As the screen goes black and before the Apple logo shows, press Command-Option-P-R and hold it ; the screen will stay blank and then after about 20s the apple logo will appear and the dong will be heard. Keep pressing Command-Option-P-R until the logo disappear and re-appear a 2nd time with the dong sound
Has anyone managed to activate the Intel UHD 630 GPU while running bootcamp?