According to WIkipedia, “On Apple–Intel architecture Macintosh computers, the EFI partition is initially blank and not used for booting. However, the EFI partition is used as a staging area for firmware updates.” When people look to create non-standard boot environments or attempt to build a hackintosh, the first step is often mounting and modifying the EFI boot partition. Before you read any further, take note: altering your EFI boot partition is not supported by Apple and The Mac Admin takes no responsibility if you render your computer(s) unbootable by mounting and modifying this partition.
To mount an EFI boot partition, follow these steps:
1. Discover the volume identifier for your EFI boot partition.
Run this command:
The output should look something like this:
/dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *251.0 GB disk0 1: EFI 209.7 MB disk0s1 2: Apple_HFS Macintosh HD 250.1 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3
In this case, the volume identifier of the EFI partition is disk0s1
2. Create a mount point.
A mount point is a directory where a non-booted volume is mounted. On Mac OS X, mount points are typically created in /Volumes. We can create a directory called efi within /Volumes by running the following command:
3. Mount the EFI partition at the efi mount point.
Run the command:
sudo mount -t msdos /dev/disk0s1 /Volumes/efi
That’s it. Your EFI volume will be mounted. Modify it at your own risk.