#Instal big sur install
#Instal big sur upgrade

#Instal big sur upgrade

If not, you would be better suited with virtualization to run the 'older' OS and let your Mac ride the firmer, recovery OS, macOS normal upgrade train. I'm assuming you have a very, very good reason to attempt to dual boot or run on hardware this OS only. You need to revive or restore it from another Mac to ensure the firmware matches the OS and the installer. I wonder what the cause for this difference is could be a lead.ĭowngrading an Apple Silicon Mac is generally not possible.

#Instal big sur install

*My M1 Mac is happy to download Big Sur using the link Glyph provided, unlike his: But this is newer than the version I want to install anyway. I tried nvram ota-original-base-os-version=20D91 but it hasn't made a difference. This is odd this is way off - this is a very recent version of macOS - 12.5.1, as in UniversalMac_12.5.1_21G83_Restore.ipswĭoes anyone have any idea if it makes sense to change this setting? Nvram -p says: ota-original-base-os-version 21G83 11.2.3 was the latest production version of macOS on March 31, 2021. Some background: The M1 Mac was ordered directly from Apple and arrived March 31, 2021, and so certainly can't have come with a version newer than 11.2.3. I'm astonished I get 0 hits with this google search: (Build+20D91)+%22is+not+supported+on+this+machine%22 I've also tried installing virtualOS from the Mac store and installing the OS fromīut I get Error: Restore image for macOS version 11.2.3 (Build 20D91) is not supported on this machine I've downloaded it and created a bootable installer, but it doesn't work-says it's not allowed on my Mac (I forgot/lost the exact error message.)Īlso, it refuses to install an older OS from a booted newer OS, but that's not as much of a surprise Apple not allowing that is not a new thing. I've tried multiple ways and nothing is working, and Apple hasn't been helpful so far, by phone or at the Genius Bar.

How can I install macOS version 11.2.3 (Build 20D91) (or older version of Big Sur, such as the one it came with) on a partition or volume (that I've already created) my M1 Mac?