Upgrading an older machine to macOS Big Sur offers several significant benefits:
| Problem | Likely Cause | Solution | | - | - | - | | “This copy of the Install macOS Big Sur application is damaged” | Corrupted download or incorrect date/time | Set your system date to a date when Big Sur was still signed (e.g., September 2021) via Terminal: date 0921000015 | | Black screen after boot | Graphics patch missing or incorrect | Boot into Safe Mode (hold Shift) and re‑apply root patches | | Wi‑Fi not working | Wrong wireless kext | Use OpenCore Legacy Patcher’s Post‑Install tool to download the appropriate Broadcom BCM kext | | USB ports stop working (macOS 13+) | Legacy USB controller | Enable the “USB 1.1” fix in the OpenCore configuration (check OCLP docs) | | System hangs at Apple logo | Incorrect bootloader configuration | Re‑create the USB installer carefully, ensuring you selected the correct “Build OpenCore” option for your model | Macos Big Sur Patcher
Certain features dependent on modern hardware, such as Sidecar, AirPlay to Mac, or advanced Continuity features, may be unstable or entirely unavailable. Upgrading an older machine to macOS Big Sur
Choose from the list and let the app download it directly from Apple servers. such as Sidecar