Hi. I'm using my MacPro 5,1 with latest BigSur build, but I want to go back to macOS 11.7.7, because some older software didn't work well with latests BigSur and I'm pretty sure it worked well until macOS 11.7.7. So I created a new APFS container on my main drive (nvme Samsung 970EVO plus) and tried to boot from USB stick with macOS 11.7.7. installer, but it didn't appear in OpenCore boot picker. The stick is surly bootable because it appears in Apple boot picker holding option key, but unsurprising, if selected there, prohibition signal appears on the screen. I tried even to insert the stick before powering up the Mac, or insert it only after OpenCore boot picker appears... I tried to modify OC config disabling SecureBootModel and enabling AppleBootPolicy, but it seems irrelevant. What other can I try? Is there a command/key to force OpenCore boot picker to rescan boot device (or scan USB ports)?
P.S. As this older software are the main reason I didn't upgrade to Monterey (where they didn't work at all), I thought to hold a container with BigSur 11.7.7 and this softwares, and when I'm sure I got a "working backup", upgrade my main container to Monterey... which build do you suggest? Reading the last posts, seems 12.7.1 has some troubles on our MacPro's...