How revert changes after update?

I spent a month setting up the display. After the update, the screen stopped working. How do I cancel an upgrade completely and return all files to the pre-upgrade state?

Make full-image backups before embarking on any major changes.

So, how do I cancel an upgrade completely and return all files to the pre-upgrade state?

Why would you think that functionality would be included in a project?

As I said, more of an OS-level sysadmin functionality.

Certainly something that should be investigated before rather than after pulling the trigger.

I realized I was wrong to do the update without backup. (((

Can someone help me with setting up the screen? I don’t remember what to do to make the screen work.