Notes on Creating a Bootable Lion, Mountain Lion, or Mavericks USB Flash Drive Installer

  First download the installer app. (Install Mac OS X Lion.app, or Install OS X Mavericks.app, etc.) 

Then right-click on the app to "Show Package Content".

Locate "InstallESD.dmg" under Contents/SharedSupport. Copy it to your home folder.

Insert the USB FlashDrive and Erase it, (MacOS Extended, GUID Partition Map.) Name it MyVolume.

Open Terminal and type:

sudo /usr/sbin/asr restore --source InstallESD.dmg --target /Volumes/MyVolume --erase

Enter your password.

Let the command run.

Validating target...done

Validating source...done

Erase contents of /dev/disk4s2 (/Volumes/MyVolume)? [ny]: y

Retrieving scan information...done

Validating sizes...done

Restoring  ....10....20....30....40....50....60....70....80....90....100

Verifying  ....10....20....30....40....50....60....70....80....90....100

Restored target device is /dev/disk4s2.

Remounting target volume...done

Restore completed successfully.

You now have a bootable USB Installer.

Useful Websites For Mac Admins & Advanced Users

 Among others, I rely on these two websites for help related to installation and management of MacOS. I have many Macs, many models, spanning many years.

It's a jungle out there, but thanks to MrMacintosh and TechRechard, my Mac admin life is made a bit easier.

They both offer links to downloadable Apple Installers, and various procedures to manage your Macs. Recommended.

Also, the Mist project on GitHub is an app that facilitates the selection and download of Apple Installers and Firmware updates.

Do you have other sites to recommend? Let me know in the comments.