I have legacy system (ASUS Rampage III / i7 920 CPU) with a working Catalina System running and previously booted by Clover. Since the last days I have switched to OpenCore and finally now I have a working legacy System booted by OpenCore. Nearly everything is working but I can't upgrade to Big Sur.   In the System Software-Update Preferences I have downloaded the Big Sur Upgrade and have started the Upgrade Process. After the first restart a new partition "macOS Install