Mac – Triple Boot Mac/Win10/Ubuntu: how to restore original copy of Windows EFI to ensure boot to Windows still works

bootcampdual-bootmacwindows

Not a duplicate – this is a new, sub-question regarding the steps in the answer here: https://apple.stackexchange.com/a/375863/4018

I followed the steps in that question, however, after completing them, selecting the Windows drive on the standard mac boot menu no longer works, what happens is that the screen goes blank and it never boots into Windows.

Also, there is not option shown in the apple boot manager for Ubuntu – video to follow.

Possible lead to explore: instead of step 6 using mv Linux command to rename the Windows EFI folders – to stop GRUB altering it, make a copy – cp -R EFI EFI.win, for later to restore back at end of steps, instead. My theory is that macOS bootmanager doesn't find Windows on a subsequent reboot after I did step 6, it adjusts itself to ignore it. By having the original there, it wont do that – AND – at the end we can restore the copy, overwriting what GRUB did. I haven't tried this yet. I also haven't tried bootrec yet.

I don't know how, yet, to solve the other problem whereby the option for booting into Ubuntu is not shown in the Apple boot manager.

Machine: 2016 MacBookPro 15" touchbar, 2.9GHz Quad-Core Intel i7, AMD 4g graphics, 16Gb RAM, 1Tb SSD.

Running: macOS Catalina 10.15.2

Windows 10 Pro 64bit installed OK with BootCamp

Attempting to install 3rd operating system, Ubuntu 18.04.3 LTS 64bit, to be an option along side macOS and Windows in the standard Apple Boot Manager boot selection screen. DO NOT want to use reFind.

Here are my screenshots of some of the key steps I followed in that answer (from above):

Differences in my setup:

that my partition name identifiers are different from the original question, but I believe I've worked out the equivalents for my case
My Bootcamp Windows has only one (1) partition, unlike the (answer mentioned above) which has three partitions.

Screenshots from step 6

steps 08-13

steps 15,16

Step 16

Step 17

Best Answer

Possible Reason Windows Will Not Boot

The Ubuntu 18.04.3 LTS 64 bit installation software changes the Master Boot Record (MBR) partition table on the installation drive to cause hybrid partitioning. This would prevent Windows from booting on 2016 model year Macs. In 2012, Apple started to phase out the need for hybrid partitioning. Evidently, the Ubuntu installer does not check for this. The answer you reference has been changed to add a step where gdisk is used to remove any hybrid partitioning imposed by the Ubuntu installer on the installation drive.

You can also remove the hybrid partitioning by booting to the live version of Ubuntu from the installer flash drive. The steps are given below.

Download the latest Ubuntu installation ISO file from the Ubuntu Home Page. The file download and used in this answer was named ubuntu-18.04.3-desktop-amd64.iso.
Use Etcher to create a bootable Ubuntu flash drive installer, then boot from this flash drive. A tutorial can be found at the Ubuntu website Create a bootable USB stick on macOS.
When the menu below appears, select Try Ubuntu without installing.
When the Ubuntu desktop appears, press the control+option+T key combination to open a terminal window.
Make sure the drive is not using hybrid partitioning. This can be accomplished by entering the command given below.
```
sudo gdisk /dev/nvme0n1p
```
This command is interactive. The interactive commands you will need to enter when prompted by gdisk are given below.
```
x
n
w
y
```
Finally, enter the command exit to close the terminal window.

Possible Reason Ubuntu Will Not Boot

Below is a copy of an image you posted as part of your question with respect to steps 15 and 16.

The image shows the following message.

Warning: Filesystem is FAT32 according to fat_length and fat32_length fields,
  but has only 51068 clusters, less than the required minimum of 65525.
  This may lead to problems on some systems.

This warning occurred because the drive on your Mac has a sector size of 4096 bytes. However, the answer referenced an example Mac with a sector size of only 512 bytes. In other words, the new EFI partition you created was too small. The instructions have been changed so the new EFI partition is at least as large as the original EFI partition. In your case, this should be about 315 MB.

To create a larger new EFI partition, you will have to reinstall Ubuntu.

Related Solutions

Mac – EFI Boot Windows 8.1 or 10 Install on MacPro4,1 / Mac Pro (Early 2009)

Got it working finally...

The first trick is to remove ALL disks from the MacPro when trying to load setup. You may leave clean HDDs or SSDs where the Mac EFI cannot find MBR or Protected MBR.

After you removed all other disks the MacPro4,1 will not directly freeze after choosing EFI Boot on the installer stick. (You will have to create it like mentioned before here to force an EFI boot of the installer.) There will then be a progress bar loading files but unfortunately you will get stuck on a black screen in a few seconds...

To be finally able to load setup you need to flash MacPro4,1 firmware to MacPro5,1 firmware.

The EFI version reported in rEFit shell will not change. But you will still have a different version after the upgrade flash. Apple does not seem to take great care about correct versioning with EFI standards as I understood from Rod Smith's comment here. This more recent Apple internal version of the MacPro5,1's EFI will be providing us with the ability to boot EFI setup from the Windows 10 Installer on the MacPro4,1 machine.

Setup will load fine then and will give you a clean bootable EFI/GPT install of Windows 10 (W8 I did not try since I am happy with the more recent version). Install bootcamp drivers and enjoy AHCI without patches.

Be sure to strip the bootmgr files from the installer disc or stick. Even when choosing EFI boot, the Apple EFI will still boot the installer in BIOS/CSM Mode when those files are present.

I will probably post more detailed step by step instructions soon...

Here they are:

Make EFI bootable USB Installer
- Download Win10 install ISO from Microsoft
- Boot into Windows DVD Setup or existing BIOS/CMI installation to access a Windows command prompt
- open command prompt (from windows run cmd, from setup press shift+F10)
- load diskpart and make a clean installer stick
  type in command prompt:
```
diskpart
list disk
select disk n #n=usb stick
clean #everything will get deleted!
convert gpt
create partition primary
format quick fs=fat32 label=Winstall
exit
exit 
```
- mount downloaded install ISO (I did it in Windows, should work in OSX too)
- drag everything from the mounted ISO onto the USB stick
- delete bootmgr and bootmgr.efi files from the stick to avoid BIOS/CMI boot and force EFI boot. See also here
Flash MacPro4,1 with MacPro5,1 firmware

Bootrom MP41.0081.B07 (EFI 1.4) to Bootrom MP51.007F.B03 (EFI 1.5) (If your machine shows Bootrom version MP41.0081.B08 you could first try to continue without upgrading. I don’t know which Apple EFI version is contained in there. Downgrading should be possible as well, definitely possible to version MP41.0081.B07. Please research if you don’t want to lose the downgrade possibility to MP41.0081.B08) The upgraded EFI finally enabled me to complete the boot process and you will have all other advantages of the 2010 and later models (hex-core CPU, faster RAM, Audio over DP) This upgrade is reversible. (If using El Capitan you need to disable System Integrity Protection. Otherwise the flash will not perform. If patch is running successfully you can see a big grey loader bar and the apple logo. Optical drives will open. See here how to easily disable SIP)
- Dowload MacPro5,1 Firmware here -Mount dmg (above steps will avoid error 5570)
- Download Mac Pro Firmware Upgrade Utility here
- Run Utility and follow instructions
- check upgraded bootrom version and identifier in System Information
Setup Windows with EFI boot
- remove ALL disks from the Mac Pro
- Plugin USB Installer stick
- Boot Mac holding option/alt key
- Choose EFI Boot
- Enter setup and select GPT installation target disk
- Install
Install Bootcamp Drivers (optional of course.. You can also manually add what you want)
- Boot into Windows
- Download Boot Camp Support Software 5.1.5640 here
- run setup (the setup was hanging on my machine while installtion of the RealTek Audio drivers. To solve that follow instructions here)

Done.

Only issue I have is with my NVIDIA GTX 680 DVI-D port (and maybe others). After installing NVIDIA drivers screen will go black without signal. Booting then will show Windows logo but will go black w(o signal when login screen should appear. The system will boot to login properly after only 5-10 sec black screen without signal when using the DVI-I port instead. After successful login I could unplug and switch the port. Confirmed on EVGA and Gainward card. Did not have time to investigate further.

Triple Booting Mac, Windows, and Linux—A boot load nightmare

As for your first question:

As you probably have already read from the rEFInd web site, the commands. to make rEFInd appear at startup are given below. You would have to enter these commands after booting to the macOS 10.13.2 recovery partition. You could enter the commands while booted to macOS 10.13.2, but you first would have to disable System Integrity Protection.

diskutil  mount  disk0s1
sudo  bless  --mount  /Volumes/EFI  --setBoot  --file  /Volumes/EFI/EFI/refind/refind_x64.efi  --shortform
diskutil  unmount  disk0s1

If the above does not work, then rEFInd is not installed as you described in your question.

As for your second question:

I an not sure why you are worried if the disk utility can recognize your linux partition. Unless you have installed some third party software, macOS can not read linux formatted partitions. Your question gives no indication that you have install such software. Anyway, the output from the diskutil list command shows that the linux partition is being correctly recognized.

If the files on the linux partition are important, then I would think the first priority would be to remove the files from the internal disk. This could be done by creating a a Ubuntu bootable flash drive and boot to a Live version of Ubuntu. If you can access your files, then I would copy the files to a second backup flash drive or other external drive.

Just to let you know:

If you do decide to start over, I would suggest installing the operating systems in the following order.

Install macOS
Use the Boot Camp Assistant to install Windows.
Install Ubuntu using the instructions given here.
(Optional) Install rEFInd.