Unable to upgrade firmware on mac mini without cd-rom

Internal SSD All Other Internal SSD
1

I’m unable to upgrade firmware on mac mini without cd-rom.

I trying to burn iso image to usb stick via disk utility but getting folowwing error:

“Could not validate source - Invalid argument”

Can you provide correct iso or dmg that can be used with mac disk utility because seems i haven’t a way to upgrade ssd firmware now?

P.S. i tried unetbootin on win and mac, tried to copy iso content with dd in terminal but mac still can’t see my usb stick on load.

2

I had the same problem.  I was never able to get the USB stick method to work.  I got an external CD/DVD drive and was able to boot that, but I could not get it to recognize my wired Apple keyboard.  However once I switched to a wireless Apple keyboard, everything worked.

3

After dozen on solutions i finally took ssd from my mac mini, put it into HP laptop with cd-rom, upgrade firmware and put back into mini. Thanks apple for sucky usb loading support and sandisk for silence…