PowerPC USB Boot — Open Firmware Instructions

Prerequisites

• A wired USB keyboard.
• A macUSB-created installer USB drive: Prepare your installer with macUSB to ensure reliable USB booting on PowerPC Macs. Single‑DVD and Multi‑DVD editions are supported.

Procedure

1. Insert the USB drive into a USB port on the computer.
2. Power on the Mac and immediately press and hold: Command (⌘) + Option (⌥) + O + F.
3. Release the keys when you see the white screen with the Open Firmware prompt.

Step 1: Locate the USB Device

You need to find which alias points to your USB drive.

1. Type dev usb0 and press Enter.
2. Type ls and press Enter to see the list of devices.
3. Look for a disk entry, usually named disk@1 (or disk@2, etc.).
   • If you do not see a disk entry: Repeat the steps above for other ports by typing dev usb1, dev usb2, etc., followed by ls, until you find the port with the disk.

dev usb0
ls

Step 2: Get the Hardware Path

1. Select the disk by typing dev disk@X (replace X with the number found in the previous step, e.g., dev disk@1) and press Enter.
2. Type pwd and press Enter.
3. The screen will display the full hardware path to the device. Write this path down exactly as it appears.

dev disk@1
pwd

Step 3: The Boot Command

You’ll now build the boot command using the path from Step 2 and the loader location. The OS X loader (BootX) is typically on partition 3.

boot [path_from_step_2]:3,\System\Library\CoreServices\BootX

Example (iMac G5)

On an iMac G5, the hardware path is often complex and starts with /ht@. You must type the full path returned by the pwd command.

Scenario:

• You found the disk on usb0 or usb1.
• The pwd command returned: /ht@0,f2000000/pci@2/usb@b/disk@1

Command to type:

boot /ht@0,f2000000/pci@2/usb@b/disk@1:3,\System\Library\CoreServices\BootX