macOS Big Sur can't install via older Catalina recovery partition?

[Bernard_Huang]

Hi all,

Anyone else have this same problem? I have created a macOS Big Sur USB installer. I boot into a Macbook (2017 or 2018 model) recovery partition, which would come up as either Mojave or Catalina recovery partition.

When I type in "/Volumes/Install macOS Big Sur/Install macOS Big Sur.app/Contents/Resources/startosinstall" --agreetolicense --installpackage <microsoft office> --volume /Volumes/Macintosh HD

This doesn't work because the older recovery partitions don't allow macOS Big Sur. I tried Opt+Cmd+R to try to download the latest recovery partition. Only then can I successfully install macOS Big Sur. But Opt+Cmd+R doesn't always work.

I would like a method that works 100% of the time, even if it takes a bit longer to execute.

[Bernard_Huang · Accepted solution]

This post is closed.
Instead of Option+Command+R, which works randomly, I am now doing this instead:
- Power on Macbook
- Hold down Option key
- Select the macOS Big Sur USB installer
- It will 100% boot into the Big Sur recovery partition, which allows for Big Sur installation.

[GabeShack]

@Bernard.Huang This wont work on machines with the T1 unless you disable the security settings to allow to boot off an external drive, however the first time you try to boot to the usb big sur installer it asks to update the boot loader on that drive, which then allows internet recovery using the option command R to work to boot to the Big Sur internet recovery. Really dumb overall that you have to do it this way.
Gabe Shackney
Princeton Public Schools

[gabester]

sed -i s/T1/T2/g @gshackney

I find the current matrix of scenarios how to boot or install one macOS based on the existing state of the device to be frustrating to deal with myself and utterly inscrutable to Windows-centric technicians who have been told (and used to learn) "Macs are so simple there's nothing really you can do to mess them up." Now it is quite easy to get a Mac into an unbootable state that necessitates a long slow internet recovery. Now they need to know whether that device is a classic Intel Mac, a T1, a T2, or an M1, and treat each of them differently. Used to be follow a couple easy steps to make a bootable drive, plug it into another Mac, hold down option key, and you're off to the races. Now, maybe you can still do that if the Mac is old enough. Maybe you can do that if the Mac is moderately new, but not too new, and someone has changed the default settings to be less secure. Maybe you need to connect it to another Mac and treat it like an iOS device instead. And quite likely Apple will change things again with the M1X/M2 models and Monterey.