Out of date firmware
I replaced the internal Fusion Drive in my iMac with an SSD. It has now fallen behind with firmware updates. How can I bring it up to date?
Ian Jamieson
Some years ago, Apple stopped supplying Mac firmware updates separately, and now delivers them inside macOS upgrades, updates, and security updates instead. For example, the macOS Mojave 10.14.1 update, High Sierra Security Update 2018-002 and Sierra Security Update 2018-005 all brought a set of firmware updates which also changed the numbering system for the firmware. Some Macs don’t appear to install these correctly, though, and one common feature to such problems is that the internal storage of that Mac has been replaced, normally with a non-Apple product, such as an original hard drive which has been upgraded to an SSD. One workaround is to replace the original storage in order to perform the update, but as ‘firmware’ is largely stored on disk that may not have any effect when the new storage is swapped back in. That also doesn’t help if the original drive has failed, or been repurposed. Sometimes installing macOS from scratch as a clean install onto a freshly formatted disk can address this.
In a few instances, the boot drive doesn’t get properly formatted in the first place and may lack the Recovery or other partitions. Sorting these problems out gets very technical, and is probably best done by your nearest Apple store.
Howard Oakley