有个老哥是重新插拔了 io board 解决的(只针对老机器)
1 month ago
Luckily, I came across a strange but working temporary fix using a windows bootcamp installation posted by Milangoa in this thread:
https://www.reddit.com/r/MacOSBeta/comments/jk72ki/black_screen_while_upgrading_to_bigsur_1101_beta/The official Big Sur Update went without any problems on my Mid2014 13" MacBook Pro. However, when turning the machine off yesterday I was not able to start it and encountered the black screen just after turning it on. I was able to start the machine by unplugging the i/o board, then I held the option key and the bootcamp boot options appeared, however the WiFi option was not shown. I hot plugged the i/o board and booted into my Windows 10 installation which resides on an external USB drive. At first boot WiFI did not work but the USB port on the i/o board and bluetooth worked without a problem. Then I restarted the machine again straight into bootcamp and on the boot options page the WiFi option was already shown and then also worked in Windows. After that I restarted again and booted up Mac OS Big Sur and everything just works like before. Waking up from sleep mode and rebooting seems to work fine for now. What does not seem to work is to shut the machine down, because afterwards its again just showing the black screen.