I really want to downgrade my M1 MBP from Tahoe to Sequoia. There are just too many issues that are frustrating me. However, AI tells me that downgrading is not trivial due to firmware upgrades when I upgraded to Tahoe. AI states:
The key complication is firmware. When you upgraded to Tahoe, there’s a strong probability that a firmware update was applied to your machine. Downgrading back to Sequoia carries a real risk of conflicts with that firmware, potentially requiring DFU mode and an Apple Configurator revive — which requires another Mac connected to yours.
Is this correct? I don’t want to inadvertently brick my M1.
It isn’t impossible, just difficult in terms of expertise and the utilitues you need, and even if you have that expertise, there’s a good chance of borking your Mac.
People I know with the expertise and tools say they wouldn’t do it.
Apart from the overly discussed Liquid Glass, performance and battery have taken a hit. One of my greater annoyances is that charging via peripherals no longer works consistently and when I grab my laptop, I find it down at 30%. It requires some effort to be able to charge via Apple’s adapter with my current setup. I also realise the increasing addition of AI will continue to tax my M1 and as the OS progresses the M1 architecture will be fully deprecated. Sequoia seems an all round a better option for the longevity of my M1.
I had hoped the Seqouia installer would overwrite everything
The installer can’t overwrite the existing firmware with an older version. You need DFU for that, and there be dragons.
From my reading of firmware versions on Howard Oakley’s site, the firmware for Silicon Macs was not changed from Sequoia to Tahoe (which seems odd, so please don’t take my word for it). If that’s true you should be able to go back.
Interestingly I didn’t encounter any difficulties when downgrading from Tahoe back to sequoia our family Macs (because my wife hated Tahoe as well) and 5 Macs at our company (colleagues either hated Tahoe or had issues).
All of them where M1 Macbook Pro besides my wife’s 16“ Intel MacBook Pro.
I put the full installer of sequoia on an external SSD drive, booted the Mac into recovery mode, wiped the internal SSD, installed Sequoia and copied the backup data back onto the computer.
The only detour was with my wife’s old Intel Mac that I had to first revert to Catalina before upgrading to Sequoia. All in all no real issue in my experience.
I may be wrong but based on my understanding you can always revert a Mac back to its initial operating system? That’s why I had to do the detour to Catalina on my wife’s Mac - but that may be old Intel-era stuff ?
This appears to be correct. It seems that Apple keep the firmware in sync with supported versions. Tahoe, plus Sequoia and Sonoma. So each update on any of those keeps the firmware in sync. This means using a USB installer should be fine.
Apparently the single core of the A18 is closer to M3/M4. It’s also to do with the rest of the architercture. Plus the Neo is going to be sufficiently underpowered to convice people they need an M chip. Perhaps for text and online/browser services it will be totally sufficient. That is not my total sphere of work. In the end Sequoia is going to be a better now til end of life for my M1. By the time Sequoia is no longer supported, I’ll more than likely be shopping for a new machine. It would also be possible to create a workflow that would make an unsupported OS still useable.
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