Disclaimer: The thoughts below are from someone who only partially understands what he (me) is talking about. You have been warned. No warranties implied. When it doubt, call Apple.
Hi. Let me tell you we just went through this with Apple. After a bit of head scratching we got to a solution. Here is what we did (in the end). The following thoughts are my after-thoughts from three support cases with Apple in the last two weeks about the M1 Macs and recovery of the OS.
To address your specific question (i.e. my three hours with apple yesterday) consider the following:
- In ASM, unassociated the device serial number from JAMF.
Reboot to recover mode, erase, reinstall the OS*
Setup Mac as a local, non-MDM-managed Mac to confirm local accounts work again.
- In ASM, re-associate the device with JAMF.
- Reboot to recover mode, erase and reinstall the OS.
A few notes about erasing these Apple Silicon M1 Macs
1. If you get to the very first recovery screen and it is NOT the list of four programs to run (disk utility, reinstall OS, etc) you should check the menu at the very, very top of the screen and look for ERASE MAC. Run through that process. It does some magic that dimply deleting the volumes does not appear to do.
2. When in Disk Utility be sure to blow away all volumes, including both Macintosh HD and Macintosh HD Data. If you miss the Data drive you will end up with another set of problems to resolve.
3. There is a terminal command 'reset password' that you may wish to run that will reset some more things.
Basically, if you try really really hard you can get the Mac to be back to a factory default state and reinstall the OS. By itself, this does not resolve your issue with the local accounts, though. Those require the steps we took with ASM as listed above.
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PS: I cannot make the online webUI WYSIWYG editor do correct number of my bullet points. Sorry about that.