Some owners of Apple Silicon Mac computers have reported serious problems when trying to restore macOS. This issue seems to apply to M1 Mac computers only. As a result, new M1 Mac owners should avoid restoring macOS until this glitch is corrected by Apple. In cases where the issue is experienced by a new M1 MacBook owner, there is fix for the restore glitch, but it's not an easy one.
Restore is rarely needed on a brand new Mac, since the purpose is to get a clean start or to correct some persistent problem. Restore is also a way to transfer to a new Mac, bringing apps, settings and data over, however, it erases the drive and reinstalls macOS at the same time, which is what seems to be causing the trouble. While the issue persists, M1 Mac owners should opt for the Migrate option when upgrading from an older Mac.
There have been several reports in the Apple Discussions forum of repeated failures when trying to install macOS after wiping the system drive and restoring from another Mac. The error message given states ‘An error occurred preparing the update.’ Some commenters on a similar MacRumors thread suggested this was caused by a failure to update to the latest version of macOS. However, at least one person with the issue said the newest update had been installed before attempting to restore from another Mac. The problem also occurs when erasing and attempting to reinstall macOS without restoring from another Mac.
How to Fix The M1 Restore Problem
For those that have already tried a fresh install or a restore from another Mac computer and encountered the error, restarting will not help and neither will installation from a USB installer or a Time Machine backup. The solution is to update the firmware, which seems to be what is affected with this bug. In order to restore the firmware, a second Mac is needed along with an Apple USB cable - reports suggest that third-party cables may not work. The tool that restores or revives the firmware is called Apple Configurator 2 and it's available for free in the App Store. Apple has a support guide that details the exact steps required to revive firmware and restore macOS.
For those without a second Mac, or lacking a compatible USB cable, a trip to a local Apple Store may be needed to get help. It’s unfortunate to spoil the excitement of a new computer with early reports of glitches and while it doesn’t seem to be a widespread problem at the moment, Apple Support may not have been alerted to the issue yet. For example, some of the user reports explain how multiple calls were made to try to resolve the problem before finally resorting to an internet search to find others with the same issue. With any new device, there are some hiccups and edge cases that appear, but for anyone experiencing this specific installation error, there is a solution that will get the new M1 Mac up and running soon.
Source: Apple Discussions, MacRumors, Apple Support