Error message "The computer is missing a firmware partition" upgrading to Mojave
Hello,
My late-2014 15" MBP Retina running Mojave that I have used for several years, has blown open due to swollen batteries. It still works, but I'm nervous about the batteries exploding or catching fire or something. Apparently this one is not eligible for the battery recall, so I've decided to try and switch to a mid-2015 MBP Retina that I also had. Both have cracked screens (over $300 to replace) so I'm using an external Apple 32" Cinema monitor, Apple KB & Mouse.
The first challenge that shot me down pretty quickly was when I tried to move the internal HD "stick" from the 2014 to the 2015. It seems that Apple changed the internal disk type, (or maybe my firmware doesn't support it?) so the 2015 does not recognize the disk from the 2014. I don't really want to spend $100 or more for a newer stick that is definitely supported by the 2015. Since I rarely use this machine as a mobile laptop (I can see about 2/3 of the screen, so I can but it's a pain), I thought I'd just install to an external Thunderbolt or USB drive (I have several of both types).
After a few false starts (USB installers with expired certs...), I managed to get El Capitan loaded via Internet Recovery onto a 1TB Thunderbolt drive, formatted GUID MacOS Extended (Case-Sensitive, Journaled). Then I was able to manually upgrade to Sierra, then to High Sierra. What I didn't realize here is that I would not be able to restore my Time Machine backup from the 2014 onto the machine in this state, because it said my backups were *not* case sensitive. I guess I might be able to do a conversion, but this has already been a very large time investment. So I tried going the next jump up to Mojave, and that's when I got the "missing a firmware partition" message.
I saw in another thread that the firmware updates *require* an internal drive, even if you are installing to an external drive. Seems odd but understandable. Can anyone verify that this is the case?
Oh, and I also tried doing the Mac-to-Mac migration, but I can't do *that* until I get the new one up to Mojave (or maybe downgrade the old one to High Sierra? Is that possible??)
Any advice anyone might have would be greatly appreciated. We recently invested in a new 2020 Macbook for my wife, so the computer budget is sort of blown for now. I might be able to swing a new internal drive for the 2015 but hate to do that unless I can afford a new LCD for it also.
Cheers, -Dave
MacBook Pro Retina