About a month ago, we talked about how MacBook Pro EFI Firmware Update 2.2 “secretly” resolved problems that 2011 MacBook Pros were having with 6.0Gb/s SATA performance.
Since we posted about the fix, we’ve been hearing from customers that some firmware updates are not fully completing… even though it appears that it is. These failed updates offered no indication that the update didn’t complete.
So a bit of sleuthing on our behalf turned up the culprit. When installing the update using Software Update, the installer informs you that it is recommended that you plug in your MacBook Pro to working power source while installing. This makes sense – the one time you don’t want your battery to go out is when running a firmware update.
However, if you download the update via its Apple KnowledgeBase page, though, the description there states that you must have your MacBook Pro connected to the power connector for installation.
From all the reports we’ve seen, it would appear that the KnowledgeBase instructions are the more accurate or at least more specific. Connecting the power supply while updating your firmware isn’t a recommendation; it’s a requirement.
Taking that requirement mindset even further is that when installing any firmware update on any Mac notebook, make sure you have it connected to its wall outlet power adapter before you start the update. Then, after running the updater, check the Hardware Overview screen in System Profiler and see if the the correct new Boot ROM or SMC version number for the update you’re running is present. If you still have the old version, then you will need to run the update again.
Naturally, this connect to power requirement is already solved for desktop machine users. But if you can think of a way to update a desktop machine like an iMac, Mac Pro, or mini without being connected to power, we’d like to hear about it!