I just checked my bootcamp driver folder and yeah the one you are looking for is in the WinPEDriver folder in the AppleSSD folder. So you were using the right one. I would say install Big Sur as there might be a firmware update in there, I am assuming you haven’t installed that yet.
Nope, I was running the Big Sur public beta until the 11.1 public beta came out (as by that point 11.0.1 was public and most of the fun of beta testing had passed). I initially wiped and reinstalled the retail version of 11.0.1 and used that to download the support software to a thumb drive (via a dongle of course). So, in theory, it should be current on firmware updates.
Download the latest bootcamp drivers as well. Personally I would also install the latest version of windows 10. Install macOS then do that bootcamp setup as you would normally including partitioning (doesn’t matter what you do as you will be deleting them)
The thumb drive has v2004 on it. I was stupid and didn't use the media creation tool to download an ISO to have as a back-up, so I had to download v20H2.
Now, are you saying it doesn't matter which Windows 10 version I use for the initial Boot Camp process? Or are you saying it doesn't matter which Windows 10 I use for install? Or are you saying it doesn't matter how I split the internal drive seeing as I'll blow it all away when booting to the thumb drive?
You really think Windows 10 v2004 isn't new enough? I just haven't gotten around to making a thumb drive install for v20H2 and would prefer to wait another month or two for more of the initial glitches to be worked out before deploying it to all of my PCs (including this MacBook, which is, seasonally, one of them)
One more thing I did which I didn’t mention as I am not sure if it actually had any effect was I kept the top root partition which was a tiny eufi partition. Not sure if you should delete that one. I did this a while ago. But I kept it and it’s been working perfect.
I did notice this partition when trying your way, and I kept it. Didn't seem to make a difference and it still seemed to fail. I'll detail what happened more specifically below.
All your steps are right! Remember to install the bootcamp drivers fully once you’ve installed it and you won’t need an external keyboard and mouse (this almost goes without saying...haha)
For sure. That much I know and am familiar with from pre-T2/pre-Apple-SSD/pre-2015 Mac Boot Camp installs. Apple seems to have made single-booting Windows on Macs progressively more difficult in the later Intel Era.
Yeah I was pretty happy about getting this working on the T2 mini. It give the machine more options in the future. I would have just dual booted but this mini only has 128GB storage so wanted all or nothing! I am sure you understand
Oh totally! 128GB is way not enough for two modern era OSes (hell, it's barely enough for one)! And it's fantastic that you're able to do this!
No problem at all, just make sure you let me know how you got on. I am sure this will work for you.
So, here's what I did. It didn't work, but my timing was crap. But I'll try it again.
1. Booted to Internet Recovery
2. Erased the drive back to being an APFS formatted drive with GUID
3. Installed Big Sur on it
4. Downloaded the ISO for Windows 10 v20H2 (as I have no other easy way of getting an ISO that matches my USB for v2004)
5. Ran the Boot Camp Assistant (which seemed to automatically find my 20H2 iso file); split the drive
Now, here's where I may have messed things up:
6. The Boot Camp Assistant auto-rebooted (which I wasn't exactly expecting); before I could Option-Boot and select my thumb drive, it was already booted to the 20H2 install partition that Boot Camp made
7. I hard shut down
8. Turned the computer back on; option booted to my v2004 USB drive
9. Blew away every partition other than the EFI partition; proceeded through as normal
10. Error in the same place.
Thoughts? I think you're on the right track with this; I might be missing something though. Again, I definitely owe you a beer and a steak dinner for all this.