WARNING: This deletes all data in all partitions.My mid-2012 15" Macbook Pro Retina with full specs (i7 4x2.6Ghz, 16 GB RAM, 512 GB SSD) has a defective GPU as ascertained in an Apple Store today. That last bit adds some complications, so go forth only if you’re brave (and have a backup). Of course, you’ll need to cover those extra GPT partitions with a protective partition on the MBR side to keep them in alignment to avoid problem when altering partitions in the future from either side. Maybe you want need more partitions on your system than MBR’s paltry 4? Perhaps to enable macOS’s filevault or to enable Windows Bitlocker? Although your BIOS booted Windows will still only see 4 partitions overall, when you boot into GPT macOS it should see even more. I did have to buy a $15 external USB DVD drive since my internal DVD drive was busted. I chose the simpler route of staying all MBR and just using DVDs.
and then install rEFInd into that EFI system partition.Older Macbooks cannot boot from a USB drive (!). So if you have two graphics cards then you MUST pick the legacy BIOS path.
I think this is a bug in the nVidia drivers and 99.99% they won’t fix it.
Windows 10 will endlessly reboot, entering automatic repair etc. In UEFI mode, they are BOTH enabled and this will kill your Windows installation when you eventually install the graphics drivers. First is the integrated Intel graphics and then you also have a discrete nVidia graphics card. If you purchased your Macbook Pro with the graphics card upgrade, you actually have TWO graphics cards inside. From there, your Mac can proceed into either native UEFI or switch to legacy BIOS (actually it’s UEFI simulating a BIOS via the EFI-CSM module). When you power on your Mac, it first runs the UEFI firmware. Some additional notes if you want to deviate from the above or want to learn more UEFI or Legacy BIOS – avoid endless reboots Their presence kills Windows System Restore functionality.
Run CMD or PowerShell as Administrator (Use the combination Shift + Fn + F10 for right-click).I suggest this specific version () since I tried another version () and it didn’t work well Once inside Windows 10, download Boot Camp Drivers.When everything installs, you should boot right into the Windows desktop. Nothing special here, regular installation process. exit (this leaves the command prompt, back to the setup).clean (this will delete all partitions or volumes on the disk).list disk (note your disk’s number … like a 1 or 2 etc.).At the Windows setup hit Shift+F10 for a command prompt.WARNING: Backup all existing data because it will be deleted! If you’re already in pure MBR (not hybrid) mode, skip this entire section. Convert your hard drive to an MBR style hard drive.At your Mac’s bootup screen pick the DVD icon with ‘Windows’ under it (do not pick the DVD icon with EFI under it).Put it in the drive and power up your Mac with Alt/Option pressed.