I have been an owner of many Mac Pros during the past 20 years. I have done firmware updates many times, including routine updates long ago and those that have become more challenging in recent years. I have used approaches described at various sites for upgrading from 4,1 to 5,1 and for upgrading to run High Sierra. In some cases, it has gone smoothly. In other cases, it has been an ordeal -- even though it was the same task and the same approach. Others have reported similar problems.
A recent upgrade from 4,1 to 5,1 was particularly difficult. I first had to upgrade to OS 10.9 so that a USB wifi would work. I tried the approach described here. As others mention in the discussion at that site, I kept getting the 5530 error. After the better part of a day of trying various things, I finally got it to work after updating to OS 10.11. For some reason, it wouldn't work under OS 10.9 on that particular computer. In order to complete one of the steps, I had to set the time of the computer back to early 2016.
I have had mixed results updating firmware for High Sierra. In some cases, it has gone smoothly. In other cases, it has been an hours-long ordeal as others have reported. When problems arise, I have found part of the long description from August 9, 2018, here to be useful. This approach involves a modified version of High Sierra that will install without the firmware update. This approach has worked for a few cases in which I wasn't able to find any other way to get the job done. After installing the modified OS, I was then able to do the firmware update.
I would like to thank those who have come up with ways of updating firmware on these machines, but it would be nice if someone could find a fool-proof approach. There ought to be a way that would make it possible to do this in a matter of minutes. In some cases, however, it turns out to be an ordeal. In some of those cases, it became a blur of trying different ideas, and I can't recall exactly how I finally got it to work.
A recent upgrade from 4,1 to 5,1 was particularly difficult. I first had to upgrade to OS 10.9 so that a USB wifi would work. I tried the approach described here. As others mention in the discussion at that site, I kept getting the 5530 error. After the better part of a day of trying various things, I finally got it to work after updating to OS 10.11. For some reason, it wouldn't work under OS 10.9 on that particular computer. In order to complete one of the steps, I had to set the time of the computer back to early 2016.
I have had mixed results updating firmware for High Sierra. In some cases, it has gone smoothly. In other cases, it has been an hours-long ordeal as others have reported. When problems arise, I have found part of the long description from August 9, 2018, here to be useful. This approach involves a modified version of High Sierra that will install without the firmware update. This approach has worked for a few cases in which I wasn't able to find any other way to get the job done. After installing the modified OS, I was then able to do the firmware update.
I would like to thank those who have come up with ways of updating firmware on these machines, but it would be nice if someone could find a fool-proof approach. There ought to be a way that would make it possible to do this in a matter of minutes. In some cases, however, it turns out to be an ordeal. In some of those cases, it became a blur of trying different ideas, and I can't recall exactly how I finally got it to work.
