Can I clean install Monterey and then add a Big Sur volume? (16" MBP x86)

[collin_]

I have a 2019 16" MacBook Pro and I just clean installed Monterey 12.2. It's the only volume (group) on the system. I want to "dual boot" Monterey (personal) and Big Sur (work), but I am not sure if you can "go backwards." Will macOS firmware allow me to add a Big Sur volume? And out of curiosity, would it allow me to add a Catalina volume even though Catalina has a different file system hierarchy compared to Big Sur and Monterey? If so, would doing either of these things cause any issues? Thanks.

EDIT: To anyone who may come across this thread in the future, this does work. ?

 

[arw]

I can only speak for Big Sur: For debugging purposes for an active Apple ticket, I created a new APFS volume to add a clean install of Monterey with the latest 12.2 update. Firmware and iBridge have been updated.
I can still select my Big Sur volume without any problems.
MacBook Pro 13“ 2020 (x86)
Edit: According to Apple, no issues are to be expected.
You‘ll probably have to use a USB installer of Big Sur to install a lower version than the currently installed one. I would create a seperate APFS volume under Monterey to minimize the probability of messing things up on the Monterey front.

 

[collin_]

@arw Thank you for the help! Is your firmware also 1715.81.2.0.0 (iBridge: 19.16.10744.0.0,0)?

I would create a seperate APFS volume under Monterey to minimize the probability to mess things up.

I didn't even know this was possible. o_o Would I just right click on my existing volume group, do "Add APFS Volume...", and install Big Sur to there?

What are the implications of installing a volume inside of an existing one rather than directly below the container?

 

[arw]

Check:1715.81.2.0.0 (iBridge: 19.16.10744.0.0,0)
Yes, I just clicked "+" to add a volume to the container. I named it Monterey. When installing a new OS, it is automatically divided into System and Data.
The advantage is, you don't have to assign any size, it's dynamically managed dependent on the demand of each volume.
I have:
- 1 Volume for files (MacStorage)
- 1 installation of Big Sur (MacBook-Pro)
- 1 installation of Monterey (Monterey)

edit: Regarding the „messing things up“ I meant, I‘d rather add the volume while running Monterey than while booted from the Big Sur installer, just because Monterey is the more recent OS. Adding a separate container might be even safer but I think you‘ll loose the dynamic size advantage. I don’t know how the recovery partition(s) are handled, but I never use them anyway. These are just my two cents.

 

[collin_]

@arw Makes sense. Thank you!!!