Unable to launch Apple Diagnostics

No way for us mortals to roll back a Firmware update, and a muxed Firmware update could easily cause anything to happen or not happen.

Yeah, one can hope, but I doubt Apple worries what old Macs can do. :(

Of course it could be fixed, it's just Zeros & Ones when it comes down to it.

Interesting, thanks.

Nah, it's the same old baloney... can't load the EFI drivers for test support.

Any news on late 2012 iMac's?

I'm not sure having the ability to run Apple Diagnostics is a huge victory given how limited it is, especially for testing RAM.

I would hold out any hopes for a fix.

I am concerned abou the problem will affect my macbook air if I upgrade the OS.

My advice is do NOT upgrade.

Expressed well, thanks. :)

Same error, and running the diagnostic due to sporadic fan running, and was told to take to a store. i certainly can't afford another macbook right now

I have the same cannot load EFI driver error when trying to run a diagnostic, however when i checked the hardware diagnostic report on the same day 24/09/2019 its saying it passed.

I can confirm that 21 other iMac 13,3s can't load Diagnostics via D or option-D at startup. They are all running the latest version of High Sierra.

Brian

I wonder if the never available to the public ASD 3s155 would still run the GUI/MacOS version, the EFI version has the same problem.