MacCentral recently posted news about a series of firmware updates for various models of Macs. According to information posted by Apple, the updates have been released to improve various aspects of FireWire disk operation, networking, and system stability.
It appears that many Mac users — particularly those that have updated their Macs with third-party RAM — are experiencing problems with the firmware update. Under some conditions, it appears that Macs using third party RAM are no longer able to recognize the installed RAM after the firmware update is applied. Mac OS will recognize only the RAM installed by Apple, and the Apple System Profiler application does not recognize the presence of the third party memory.
The firmware updates are specifically for slot-loading iMacs, FireWire-equipped PowerBook G3s and iBooks, and AGP-equipped Power Macs and Cubes, and are numbered either version 4.1.7 or 4.1.8, depending on the specific Mac model. Although the updates were released on the cusp of Mac OS X’s release, they are not necessary to enable Macs to operate with the new operating system. In fact, the firmware update must be applied while running Mac OS 9.1.
Again, the problem is not universal to all Macs with third-party RAM installed — many users, including some MacCentral readers, have been able to apply the firmware update with no problem whatsoever. Still, with the firmware update released late on Friday, it may be another day or so before Apple has any official comment or instruction for people whose Macs have been affected by this problem. As a result, prudence may be the best course of action for Mac users who think their systems may suffer.