Activate Mac after disk is erased

[joejoe]

I already erased the disk. Mac asks me to connect to the Internet to activate it. I assume Mac doesn’t have any Jamf or MDM data. How could this Mac know it needs to re-install Jamf or MPM back?

[TrentO]

All ARM macOS machines have to activate after the disk is erased. This is not a Jamf (or other MDM process). MDM automated device enrollment is checked during Setup Assistant. 

[AJPinto]

MacOS needs an internet connection to Activate. Once it has an internet connection you will know if it will be redirected to MDM for Activation, or if Apples Activation Servers will handle the Activation (i.e. no MDM).

As @TrentO said, if you used Erase All Contentes and Settings on an Apple Silicon Mac there will be a step to Activate the Mac in a recovery like environment. From my experience only Wi-Fi and direct ethernet connections work for this activation. Docks never seem to clear this activation for me.

[AlexHoffman]

Activation is not an MDM thing, it's an Apple thing. All Apple Computers and Devices must phone home to Apple servers to verify they are a legit Apple device and then setup may proceed. At that point, if your devices are enrolled in a Jamf Pre-Stage and Apple Business Manager, they will go through pre-stage enrollment. If they are not in pre-stage, they will run through the standard Apple Setup Assistant.