Tuesday, March 21, 2017

Creating a Custom Mac Boot Label and Image

Having created a bootable Clonezilla drive for Mac, I wanted to see if I could change the label and image that appears on boot up.
Now keep in mind that the drive has to use a GPT partition table and be an EFI boot device. It is important to note that the icon and label that appear on Mac startup are not part of any EFI spec. Both of these bits of information are an Apple proprietary thing and they must applied using a Mac. When they are applied, macOS (OS X) writes some hidden files to the root of the drive to make the magic happen, so it doesn't affect the function or compatibility of the drive, except to use a very tiny bit of space.

The easy part is the boot label (which is different than the drive label). To apply a Mac boot label, go to Terminal, and run the following command to confirm the existing name of the drive:
ls /Volumes

Then use the bless command to set the boot label:
sudo bless --folder "/Volumes/Your Drive" -label "New Boot Label"

If you want to change the volume label, you can of course do that from the desktop anytime.

The harder part is the icon, only because you have to design it and to convert it to the icns format. First, compose your icon using a 512x512 pixel size. Then convert to icns. I used this site to do the conversion.
If you do a Google image search for a generic 512x512 drive icon, you can use that as a base for your custom design, which is what I did. If you are making a Clonezilla boot drive and you really like my icon and want to skip all this, you can download it here.

To apply the icon, open the Get Info window for the drive, then drag the icns file over the existing icon on the top left of the window.

More info:

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