Best way to roll back to an earlier version of macOS on Apple Silicon?

[pshufd]

I found a really bad bug on 13.3 and need to roll back or I won't be able to run one of my two production programs. I tried installing 13.2.1 to an external SSD yesterday but I couldn't set it as my startup drive.

I have Time Machine backups but they are data backups which I assume to mean that they don't include macOS. The recommendation is to install macOS and then use Migration Assistant to move my user are over. That's fine but I would need to get 13.2.1 on my system.

I could try to create a bootable flash drive but I'm curious to know if that works on Apple Silicon.

I could generally do this stuff in my sleep on Intel Macs.

 

[pshufd]

I created a bootable flash installer and will give this a try.

 

[pshufd]

Installation is proceeding.

This is my first rollback on Apple Silicon and I did learn a few things. I've done installations before but it seems easier reinstalling the current version or a later version than going back.

 

[pshufd]

Restoring from Migration Assistant.

It's really comforting when your backup system works as it should. It will take a couple of hours to do the restore as it's an old HDD.