Downloading Apple iMac Firmware 4.1 for Mac from our website was free. The application lies within System Tools, more precisely General.
From the developer:
The iMac Firmware Update 4.1.9 will only run on iMac computers with slot-loading CD or DVD drives running Mac OS 9.1 from a local drive. If you are using Mac OS X you must boot from a local Mac OS 9.1 writeable partition (not a CD, or network disk) prior to following the update instructions.
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