Stalling on M1 Mac - "Failed to authorize for installation"

[rjtort]

Working fine on Intel Macs ,but on M1 Macs it stalls out. Startosinstall.log says;

Error: failed to authorize for installation. Provide a password with --stdinpass or --passprompt.
By using the agreetolicense option, you are agreeing that you have run this tool with the license only option and have read and agreed to the terms.
If you do not agree, press CTRL-C and cancel this process immediately.

Apparently Apple now requires authentication to use startosinstall command on Apple Silicon Macs. If you run it as root from terminal, it'll ask a second time for you to enter credentials, but running the macOSUpgrade script via Self Service, just stalls out.

Any way to work around this?

More info in thread here; https://www.jamf.com/jamf-nation/discussions/37297/big-sur-upgrade-bash-command