Well, I have the same with my MBPr 2014 Mid 13โ I got an USB clean install, to boot disconnect the I/O board and others say you have to order a new one. HDMI Chip should be the problem I dunno (Source https://www.heise.de/forum/heise-online/... )
During the boot process, I reconnected this I/O Board and during the Clean Install with USB Stick of Big Sur during the restart of the install, the MBPr restarts without a black screen. ( I/O board reconnected)
In Big Sur itself, it detected everything fine, WiFi MAC Address was also zeroโd (the MAC Address is a string of โ0โsโ), after a second clean install, everything works (Havenโt tried HDMI), but as soon as you shutdown or restart, it wonโt restart anymore, the Black Screen failure persists.
Can someone suggest a good SPI Programmer to flash the Boot ROM (EFI)? And has someone the BootRom?
I guess this problem is the Boot ROM sadly you canโt downgrade it. Nor find a Firmware/BootRom so you could flash your MBPr with and SPI Programmer on it.
UPDATE:
(In short replacement I/O board I went for the late 2013 13โ I/O board, I have mid 2014 13โ, so it works as well. )
I ordered a replacement I/O board from ebay for my mid 2014 13โ I ordered a late 2013 I/O board yesterday. Today it arrived. It works, and I even went a bit crazy by reinstalling Big Sur and taking the risc of bricking this new I/O card again. I Created a USB Installer Clean Install wiped everything and now it runs and still functioning. No Bricking so far.
(What I have bought https://www.ebay.de/itm/303741260478)
I tested the old board still black,
Before I forget does someone know a good SPI Programmer to flash the Bios chips of all MacBooks? Answer to this would be much apprechiated! ^-^
โIn between my try and error methods / in the mean time โPostageโ
Before the new one I tried, 5 reinstalls, during it, I tried to reconnect the old โbrokenโ I/O board, (Precise, I disconnected then startet optionskey to get into the boot menu, then reconnected the I/O board.) During the whole Installation nothing went bad, the last reboot I had to disconnect and reconnect this board like before but I went for the system, I even got Big Sur working and was able to login and such, the strange thing is USB worked, HDMI worked but kinda buggy, Wifi Worked, and SD Card functionality, like everythings fine. BUT big but I decided to restart again, I was thinking I would have fixed it โฆnope After a manually restart still black screenโฆ
I thought an older MacOS could โreinstall/reflashโ the old BootRom, So I installed El Capitan and black screen. no success. SPI Programmer I dont have one, but I will buy one.
โtry just disconnecting the battery (which requires some disassembly), then hold down the power button for 5 secs to completely discharge, then re-assemble and restart.ย โ
-Tried it didnโt worked
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๋๊ธ 9๊ฐ
I have the exact same problem, mine is a mid 2014 MacBook Pro.
It is not possible to enter recovery mode the startup chime, does not play.
I have tried resetting SMC but no luck
Søren Hilmer ์
The Big Sur update seems to have bricked my mid-2014 13โ MacBook Pro as well. Apple support tried resetting PRAM etc and then asked me to take it for in-person service. All I get is the backlight when I turn it on, the caps lock key doesnโt even light up.
Josh A ์
@josha57 - You'll need to call or visit an Apple Store to have them fix the corrupted firmware.
Dan ์
I went to an apple authorized repair shop today (there are no Apple Store in Denmark). They could not restore the firmware as the computer is more than 5 years old, the firmware restore tool considers it โvintageโ
Søren Hilmer ์
UPDATE: Apple has posted a new T/N on the issue! If you canโt install macOS Big Sur on certain 13-inch MacBook Pro computers from 2013 and 2014
Here's a bit more: How to fix macOS Big Sur installation issues on older MacBook Pro
Dan ์
๋๊ธ 4๊ฐ ๋๋ณด๊ธฐ