those solutions are useless.... where's is the real support... the certified services said Big Sur corrupted the firmware... please provide solutions... not excuses
my unit get stuck in black screen before staring up
the units was revised for a certified technician without any satisfactory result... cause apple doesn't publish any procedure to solve the issue, although is an issue for several MacBook Pro mid 2014
it seems like the firmware is corrupt... the service center restore my macbook to Mojave with some positive results, cause the unit starts up sometimes.... but something is not good Bluetooth doesn't work, spotlight doesn't work, I can't find some files in the hard drive, and I can't rebuild it,
after reviewing with the technician and read some blogs, we can said the Big Sur update corrupted the firmware... but apple doesn't provide a solution.... and the certified technicians doesn't have tools to solve cause the units is vintage and they can not repair the firmware
please solve
MacBook Pro 13″, macOS 10.14