Finally got it to work after more than a week of attempts. On the off chance it helps anyone, here's the rough outline of what I went through.
I did try following the tutorial but had no luck. I'm sure I made mistakes along the way and/or had a conceptual misunderstandings of what I was supposed to do for some of the steps. If you spot any obvious mistakes, etc. please feel free to point them out for my benefit and the benefit of anyone else who might read this.
What didn't work:
I'm running Clover and tried following the tutorial a handful of times, but couldn't get a direct update to work. It would go fine up until the reboot, then return me back to the
El Capitan build (I have 5 seconds to choose the boot volume).
I tried the various loading options, e.g. without caches, inject kexts, both, and so on. I tried updating the boot loader to a variety of different versions, but for most of them the computer wouldn't even reboot (just hung on a black screen). I tried it with the default 14,2 config.plist in the tutorial and with my own. Nothing worked. It's likely I was close and just missing an easy step or two, but after countless failures I decided to try a different approach.
What worked:
I put my SSD boot drive into an external USB drive dock* and updated the SSD directly from a MacBook. Progress: it could boot my MacBook Air but not my PC.
I updated to Clover bootloader to v.r3766 (v3793 and others didn't work), and swapped in the tutorial's
14,2 config.plist. That kind'uv worked.
When I plugged my SSD into my PC, I now got the prompt
"Reboot and select proper boot device…" Selecting F12 during the Motherboard splash screen lets you select the boot volume directly. It now finally booted into
macOS Sierra!
I then ran
Multibeast 9.0 Sierra to update my kexts and the bootloader. Now I could boot via the Multibeast-style bootloader.
Config.plist
Because I used the
default 14,2 config.plist, I needed to update it with my old settings. Unfortunately, copying the old version directly did not work (it wouldn't boot). And copying new elements from the default
config.plist to my old file didn't work either. So I decided to start with the new default file and copy over individual settings one by one, reboot and test. (Save backup copies of your
EFI directory after every change so you can easily revert back! I even took screenshots of the Clover Configurator sections after each step for easy reference).
Eventually I got most of the essentials settings copied over, e.g. SMBIOS and Kernel and Kext Patches and moved on.
Note: This process was made much easier with a program called "VisualDiffer". I used it to compare my old config.plist side by side with the new config.plist. You can even directly copy segments from VisualDiffer and paste them directly into your new config.plist. Some old settings transferred without issue, some broke the build. Lots of tedious trial and error.
Audio
Still no audio. So I ran
Multibeast 9.0 Sierra and re-installed the audio codec (for me, ALC898) once again. Fixed!
Ethernet - iCloud and apps couldn't connect to Apple to validate.
Although I had an internet connection, my apps and iCloud couldn't connect to the App store to validate my purchases. iCloud wouldn't accept my password, so I tried changing it - no luck. Same for my apps.
The problem: the ethernet card settings reset during the upgrade. Use
DCPIManager to check the settings.
Per
Jaymonkey's excellent tutorial on iMessages, I had to reset and update the cards. COPY THE INSTRUCTIONS TO A TEXT FILE, because you may lose your internet connection in the process! Delete the specified files, test. I had to repeat the steps several times before I got my ethernet card to reset to the "
BSD name" of "
enc0". That did half the trick, but the "built in" checkbox also needed to be checked.
(see attached image below). So I ran
Multibeast 9.0 Sierra and re-installed the network kext once again. Success!
Well, kind'uv. All of the settings were now correct, but still no internet. Not sure what else to do, I swapped the ethernet cable to the other ethernet port. This restored the internet and my iCloud and apps were able to validate! Finally!
Safari crashes [unresolved]
Last known issue: Safari sometimes crashes when playing videos. Youtube is fine, videos on Facebook are fine, but videos on some random sites crash on Safari. I'm guessing flash? Chrome seems to handle them. I tried the
suggested solution here (some of links give you the text you can copy/paste directly into your config.plist). Unfortunately it didn't work for me. I'll return to this later if it becomes a recurring problem.
Footnote
* Highly recommend: I have a Thermaltake USB Dual Bay Hard Drive Docking Station. It's been absolutely indispensable. Sometimes even trivial changes in Clover Configurator (config.plist) can break your build. With a dock, you can pull the drive, plug it into a working Mac via a USB port, and copy/restore your last working EFI directory and you're back in business in moments.
Note: I do have multiple backup drives with Carbon Copy Clones of recent working builds, but they don't always boot. I suspect if you bork the boot loader of the main drive, it will supersede the backup drive's bootloader? Selecting F12 to bypass the broken bootloader and select the boot drive directly sometimes works, but not always. The docking station saves you in those cases. And sometimes it's just plain faster than booting up from an old HD.