Restoring M1 Mac without (or with 100% worn) SSD

I just wondered, in case you have 100% worn SSD is it possible to turn on your Mac and reinstall macOS to another drive?

Solution 1:

Yes, you can boot the M1 Mac from an external Thunderbolt 3 drive.

Attach your Thunderbolt 3 drive to an M1 Mac, erase the drive and format as APFS with Disk Utility, and then run the macOS installer, selecting the external drive as the target, and install.

If you haven't got a working M1, you can use the M1 Mac that won't boot from the internal drive, by powering it up while pressing and holding (long press) the power button. When you get the startup menu, click the Options icon and "Disk Utility" in order to erase and format the external drive as APFS - and then from the Options menu select "Reinstall macOS" to install macOS.

After installation, you can use the external drive to boot the M1 Mac that hasn't got a SSD drive. When you power on the M1 Mac, you need to long press the power button until the display shows the startup menu. From here you can select the external drive to boot from.

Note that if you installed macOS on a different computer than the one you're trying to boot up, you will be required to enter various credentials (such as your user's password, your Apple-ID password, etc).