Downgraded back to Monterey, have a question about EFI version

[CLS7]

I upgraded my iMac late 2015 in yesterday to MacOS Ventura using OpenCore legacy patcher.

I regretted the upgrade and wanted to downgrade back to Monterey by using a backup from an external drive. Everything seems to be fine after the downgrade.

But then I saw that I have a newer EFI firmware version (499.40.2.0.0) than I expected (should be 451.140.1.0.0) so I guess this firmware version coming from the Ventura installation.

To my question, can this be a issue to have a newer EFI version when running Monterey?

 

[asus389]

Not sure, I have the same question. Updated from Catalina to Ventura, and went back. Boot rom version stayed at 499.40.2.0.0 which is the version installed with Ventura.

This article suggests that for different types of Macs it may/may not be possible to downgrade the firmware.

Firmware and Recovery upgrades and downgrades on different Macs

What would happen to a Mac’s firmware if you installed Monterey beta to its internal or external disk? Could that be reversed?

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