Apple has released eMac HLDS Combo Updater 1.0.
According to Apple's release notes the update prevents blank CD-Rs from automatically ejecting from an eMac after auto-ripping in iTunes.
The 348K firmware update is required for the Hitachi-LG Data Systems CD-RW/DVD-ROM Combo drive.
The update requires Mac OS X v10.3.3 or later. Apple recommends it for all eMacs with the Hitachi combo drive. If the eMac does not have this drive and the update is run an error message will be displayed.
A link to the update was available on Apple's Web site but appears to have been removed.