iBoot

• It's the apple's boot firmware
• Version: iBoot-11881.1.1

MacOS installation

• A macOS installation is composed of:
• System Volume: "Macintosh"
• Data Volume: "Macinttosh - HD"

• Preboot Volume: a nested directory (named as the id of the VG) inside of the preboot volume

• The system & data volumes are grouped in a single Volume Group (VG)

LocalPolicy

• A LocalPolicy can be created by using for a macOS installation using bless or bputil.
• It basically sets the a macOS installation (the VG) as the default boot VGID

System Volume

.IAPhysicalMedia

The file IAPhysicalMedia.plist can be placed at the root of the system volume. It indicates which entrypoint executable (*.app) needs to be executed on the next boot in 1TR

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>AppName</key>
        <string>Finish Installation.app</string>
        <key>ProductBuildVersion</key>
        <string>00A191</string>
        <key>ProductVersion</key>
        <string>12.1</string>
</dict>
</plist>

This file is usually renamed (e.g., to "IAPhysicalMedia-disabled.plist") to that it won't run on the second boot