Does anybody know if this guide works for updating from Sierra to Mojave? I never bothered updating to High Sierra.
I just did that yesterday:
I upgraded one of my Lenovo Thinkstation E20 (4222, Desktop 3 in my signature) from Sierra directly to Mojave.
After install, it would not boot anymore.
This is because I came direct from Sierra and forgot to take the steps to enable APFS boot. I was able to get it to boot by inserting the Mojave USB stick I had previously built using UniBeast, and pressing F12 so I could tell BIOS to boot from the internal SSD - then somehow it would load the apfs driver from the USB stick and I could choose the correct partition to boot from.
I ended up copying the contents of drivers64 from the EFI partition on the USB stick, to the empty drivers64 in the internal SSD's EFI partition. After that, it would boot natively from the internal drive.
Everything seems to be working except for video. It's an Nvidia 8600GTS card. Since upgrading, the fan is on constantly and it doesn't "look" right. Did they drop support for the old Nvidia cards? Do I need a new driver or something? This one "just worked" with Sierra, I am pretty sure I didn't have to do anything at all except maybe turn on an "Inject nvidia" flag which as far as I can tell is still turned on.
Today, I updated Clover to 4700. Now it sticks on apple logo and won't boot. Will work on it more this evening, hopefully I can still get it to boot using the USB stick and roll it back to whatever version I had or figure out what the issue is.
I note that the OP says there's another forum section for asking questions, I will do that if I don't figure this out. Leaving this post here for reference detailing why the guide didn't work for me, because I had skipped High Sierra and its steps for enabling APFS support.