MBP 2014 firmware downgrade

[Rimmsi]

Hi, I have an MBP 15 "mid 2014. After upgrading to Big Sur I found that the processor could not be undervolted, it is caused by the last firmware .431 that was installed together with Big Sur. Is there a way to downgrade to Catalina or older firmware? Thank you .

 

[Audit13]

Only way I know of would be to try using an EEPROM programmer.

 

[Rimmsi]

Does anyone have experience with this and could place instructions here?

 

[Rimmsi]

Hi, today I successfully unlocked the 431 firmware using the EEPROM programmer. Finally, I have CPU undervolting again. I used this tutorial.

GitHub - IsmaelHG/UndervoltPatchMacBook: Firmware patch for unlocking FIVR control + Overclocking on Apple computers

Firmware patch for unlocking FIVR control + Overclocking on Apple computers - IsmaelHG/UndervoltPatchMacBook

github.com