27-Inch iMac Firmware Updates Address High Processor Usage, Display Backlight, and Target Display Mode Issues

Apple today continues its barrage of updates with the release of a pair of firmware updates for its 27-inch iMac models addressing a trio of issues.
27-inch iMac EFI FW Update 1.0, weighing in at 2.1 MB and requiring Mac OS X 10.6.3, is recommended for all quad-core 27-inch iMacs and addresses a pair of issues related to high processor usage and display backlighting.
- Resolves an issue that sometimes caused high processor utilization while playing audio through the headphone output mini-jack.
- Resolves an issue that prevented the display backlight from turning on after powering on the iMac.
The 27-inch iMacs are not the only current Mac models to have experienced problems with processor performance during audio-related tasks, as Apple's Mac Pro line received a software update in mid-February to address its own issues with heat and performance while handling audio-related tasks.
Apple's other firmware release for the 27-inch iMac today, known as 27-inch iMac SMC Firmware Update 1.0, makes unspecified compatibility fixes to Target Display Mode. The feature, currently available only on 27-inch iMacs, allows the machine to be used as a secondary display via its Mini DisplayPort connector. The update weighs in at 397 KB and requires Mac OS X 10.6.3 and the 27-inch iMac EFI Update 1.0 also released today.
Popular Stories
Apple today released new firmware designed for the AirPods Pro 3, the AirPods 4, and the prior-generation AirPods Pro 2. The AirPods Pro 3 firmware is 8B25, while the AirPods Pro 2 and AirPods 4 firmware is 8B21, all up from the prior 8A358 firmware released in October.
There's no word on what's include in the updated firmware, but the AirPods Pro 2, AirPods 4 with ANC, and AirPods Pro 3...
Apple recently teamed up with Japanese fashion brand ISSEY MIYAKE to create the iPhone Pocket, a limited-edition knitted accessory designed to carry an iPhone.
iPhone Pocket is available to order on Apple's online store starting today, in the United States, France, China, Italy, Japan, Singapore, South Korea, and the United Kingdom. However, it is already completely sold out in the United...
iOS 26 extended pinned conversations in the Messages app to CarPlay, for quick access to your most frequent chats. However, some drivers may prefer the classic view with a list of individual conversations only, and Apple now lets users choose.
Apple released the second beta of iOS 26.2 this week, and it introduces a new CarPlay setting for turning off pinned conversations in the Messages...
Starting with the upcoming tvOS 26.2 update, currently in beta, additional profiles created on the Apple TV no longer require their own Apple Account.
In the Settings app on the Apple TV, under Profiles and Accounts, anyone can create a new profile by simply entering a name and indicating whether the profile is for a kid. The profile will be associated with the primary user's Apple Account,...
Apple is preparing for Tim Cook to step down as CEO of the company "as soon as next year," according to the Financial Times.
The company's board of directors and senior executives "recently intensified preparations for Cook to hand over the reins," the report said.
While the report said that Apple is unlikely to name a new CEO before its next earnings report in late January, it went on to ...
Most of Apple's Macs are slated to get M5 chips across 2026, and there's a possibility we'll even see the first M6 chips toward the end of the year. Updates are planned for everything from the MacBook Air to the Mac Studio.
MacBook Air (Early 2026)
The MacBook Air will be one of the first Macs to get a 2026 refresh, with an update planned for the first few months of the year. The MacBook...
Walmart's Black Friday sale has officially kicked off today, with an online shopping event that's also seeing some matching deals in retail locations. There are quite a few major discounts in this sale, including savings on headphones, TVs, and more.
Note: MacRumors is an affiliate partner with Walmart. When you click a link and make a purchase, we may receive a small payment, which helps us...
We're officially in the month of Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon.
Note: MacRumors is an affiliate partner with some of these vendors. When ...
Apple released the first iOS 26.2 beta last week. The upcoming update includes a handful of new features and changes on the iPhone, including a new Liquid Glass slider for the Lock Screen's clock, offline lyrics in Apple Music, and more.
In a recent press release, Apple confirmed that iOS 26.2 will be released to all users in December, but it did not provide a specific release date....
While it was rumored that Apple planned to release new versions of the HomePod mini, Apple TV, and AirTag this year, it is no longer clear if that will still happen.
Back in January, Bloomberg's Mark Gurman said Apple planned to release new HomePod mini and Apple TV models "toward the end of the year," while he at one point expected a new AirTag to launch "around the middle of 2025." Yet,...