If you don't mind a slower install, you can try booting off a USB drive:
Method 1:
# If the computer is on, turn it off.
# Press the power button and immediately start holding the Command, Option, O and F keys.
# If successful, you should see a screen that lists your computer and says "Welcome to Open Firmware"
# At the prompt, type ``boot usb0/@disk1:,\\:tbxi``
# If that doesn't work, try the following commands:
## ``boot usb1/@disk1:,\\:tbxi``
## ``boot ud:,\\:tbxi``
This will be updated will compete instructions one I know the file format your downloaded MacOS image is in.