Rebuilding your macOS Recovery volume or partition with create_macos_recovery

I recently got an email from a former colleague, requesting assistance with a problem they were seeing. They were cloning drives with macOS Catalina, but their cloning process was not including the Recovery volume. Was there a way to create a new Recovery volume on a macOS Catalina boot drive that didn’t have one?

I did some research on this and found that there was a script to do this on High Sierra and Mojave, but it didn’t appear to work anymore.

With some more digging, I was able to figure out why. The script was downloading and expanding a macOSUpd10.13.6.RecoveryHDUpdate.pkg installer package from Apple’s Software Update service in order to get access to a dm tool included with the installer package. This installer package was no longer available from the Software Update service, but a similar package named SecUpd2019-005HighSierra.RecoveryHDUpdate.pkg with the same dm tool was available.

Once I verified that I could get the same results using the SecUpd2019-005HighSierra.RecoveryHDUpdate.pkg installer package, I wrote a script (based on the original one I had found) to help automate the process of rebuilding a macOS Recovery volume or partition. For more details, please see below the jump.