Using separate 'Bootcamp' Drive (legacy/bios) from cMacPro with rMBP

[piller97]

Hey all,

Looking for some advice trying to figure out the best way to go about a bit of an issue I've encountered.

Background:​

The Drive in Question:​

A bit over a year ago I installed windows on a separate drive in my cMacPro using roughly(?) this procedure. I honestly cant quite remember, might have been that exactly. What I do know is that it was a legacy install via a cd installer.
Since then its worked as good or better then is expected, a couple hiccups here and there, but basically a windows pc that runs MacOs on the side.
I will heron out refer to this as the 'Bootcamp Drive'. Even though as best as I can find, its basically as good as a native windows drive

The Situation:​

i) Currently I have some software on that drive that I would like to use in a different local. (Automotive diagnostics software to interface with a car, obviously the car is down in garage)

ii) My initial reaction was, take the drive out of the cMacPro put it in an enclosure (o.k. I only have the sata adapter bit left of my drive enclosure, but i promise I'll keep it clean) and connect it to my rMBP and boot from it there.

The Issue:​

I figured this wouldn't be too hard, both my cMacPro and rMBP are running High sierra(...What can go wrong?).
But at last, that is not the case. Attached to the rMBP the Bootcamp Drive is not bootable.

When booting holding down option the drive doesn't even show up on the rMBP. If you try to select the Bootcamp Drive otherwise as a startup disk it throws an error along the lines of "... The Bless tool was unable to set the current boot disk ...".

It would appear this can be traced back to the legacy install process that allowed such easy creation of the disk on the Mac pro.
If I understand correctly(forgive me, cant find the links ATM) the rMBP firmware doesn't allow for booting from non EFI drives.This is an issue here because the legacy install on the MacPro created a bios drive.

Going Forward:​

The crux of my question is: what is the best course of action?​

Is there a somewhat hassle free way of making this drive usable on both computers?
From what I've seen it wouldn't take a crazy amount of work to make it function with the rMBP, but would that alter its usability on the cMP? (From what I've seen/remember, the whole reason behind legacy install was because EFI install caused issues with the mac pro)

If it comes down to it, I can drag my MacPro, monitor, keyboard, mouse and maybe an extension cord or two down to the garage.
However if I want to use the software while out on the road, that may become more difficult.......("hello officer, I see you checking out my passenger; the 5.1 sure was a beaut.")

TLDR​

Guy does legacy install of windows on separate drive on cMP, guy wants to use drive on rMBP where firmware precludes the usage of legacy/bios drives.
Guy wants to know easiest way to maximize utility while maintaining functionality of drive.

I sincerely appreciate any and all thoughts and opinions.
~p

 

[joevt]

You would have to convert the legacy drive to UEFI. There's probably a website that explains the procedure. Is the drive a hybrid MBR/GPT? If so, then it can be converted to pure GPT. Then you need a Windows installer to add Windows boot files to the EFI partition which will point to the Windows partition.

It may be possible to then boot the drive as EFI on both the cMP and the rMBP but it might be dangerous on the cMP. You can set OpenCore as the first booter and configure it to block the Secure Boot (X.509) certificates that overwhelm/corrupt the NVRAM. Then always use OpenCore to boot the EFI Windows.

What kind of enclosure is Windows installed on? Windows has different behaviour/requirements/method for USB install.

I would test with a different Windows installation before attempting to modify the Windows installation that you care about.

 

[piller97]

You would have to convert the legacy drive to UEFI. There's probably a website that explains the procedure. Is the drive a hybrid MBR/GPT? If so, then it can be converted to pure GPT. Then you need a Windows installer to add Windows boot files to the EFI partition which will point to the Windows partition.

It may be possible to then boot the drive as EFI on both the cMP and the rMBP but it might be dangerous on the cMP. You can set OpenCore as the first booter and configure it to block the Secure Boot (X.509) certificates that overwhelm/corrupt the NVRAM. Then always use OpenCore to boot the EFI Windows.

What kind of enclosure is Windows installed on? Windows has different behaviour/requirements/method for USB install.

I would test with a different Windows installation before attempting to modify the Windows installation that you care about.

I believe the drive is MBR only.

Not 100% sure of what you mean by "enclosure".
If you mean physical install location: primarily in one of the cMP bays.
If you mean the disk medium itself: its just a sata ssd.

I figured I'd have to convert it. A quick search online looks to indicate this may be possible via 'mbr2gtp' built into windows 10. Not sure how seamlessly it would be in practice however as I'd be doing it well installed in the cMP.

The fact that it only currently works in the cMP is kinda a catch 22 for converting it. Even if I configure OpenCore to deal with it post transition, the cMP would be handling the transition itself....going out on a limb assuming I cant primitively block certificates that don't yet exist?

EDIT:
Shortly after my reply I had a good idea, or so I thought.....
It would appear support for legacy/bios was dropped around the 2015 models.

So I just grabbed an old 2012 MBA and tried to use that to boot into the drive.
While the drive did actually appear in startup manager. It displayed with the Firewire icon; whatever it represents(mass storage?) opposed to the Bootable drive one and as only one drive ('Windows'), as opposed to 2 on the cMP (Bootcamp&bios). Trying to boot into it leads to black screen and "No bootable device -- insert boot disk and press any key".

Which I guess leads me to another question. If legacy support is available pre-2015 what might the issue be here?
Of even better I guess....what is it about the cMP firmware that allows it to use the drive while others cant?

 

[joevt]

I believe the drive is MBR only.

Then it might not be bootable for EFI mode. I don't know if Windows allows booing EFI from MBR only disk. I mean, nothing would stop EFI from loading and running an EFI booter from the disk if there's a partition readable by EFI (FAT or HFS). The disk wouldn't have GPT partition UUIDs but I don't know if that matters. The partitions have Volume UUIDs which could be sufficient.

Not 100% sure of what you mean by "enclosure".
If you mean physical install location: primarily in one of the cMP bays.
If you mean the disk medium itself: its just a sata ssd.

I thought you would want to use the disk in an external enclosure for both the cMP and the rMBP.

I figured I'd have to convert it. A quick search online looks to indicate this may be possible via 'mbr2gtp' built into windows 10. Not sure how seamlessly it would be in practice however as I'd be doing it well installed in the cMP.

You can also try iPartition.app on the Mac. You may need to shrink a partition to make room for an EFI partition. iPartition can shrink some partition types.

The fact that it only currently works in the cMP is kinda a catch 22 for converting it. Even if I configure OpenCore to deal with it post transition, the cMP would be handling the transition itself....going out on a limb assuming I cant primitively block certificates that don't yet exist?

I'm not sure. If it boots legacy, then there's no certificates. It's only when you boot using EFI that you need to make sore OpenCore is booted first.

Shortly after my reply I had a good idea, or so I thought.....
It would appear support for legacy/bios was dropped around the 2015 models.

So I just grabbed an old 2012 MBA and tried to use that to boot into the drive.
While the drive did actually appear in startup manager. It displayed with the Firewire icon; whatever it represents(mass storage?)

FireWire? Is the drive in a FireWire enclosure or a USB enclosure?

opposed to the Bootable drive one and as only one drive ('Windows'), as opposed to 2 on the cMP (Bootcamp&bios).

I don't know what you mean by Bootcamp and Bios. Where do you see those?

"Windows" is the name shown in the Apple Startup Manager (when you hold option key at boot) for any disk that contains an MBR with boot code.

Trying to boot into it leads to black screen and "No bootable device -- insert boot disk and press any key".

Which I guess leads me to another question. If legacy support is available pre-2015 what might the issue be here?
Of even better I guess....what is it about the cMP firmware that allows it to use the drive while others cant?

Legacy support only supports certain drives - usually internal SATA or DVD. Basically the CSM doesn't know how to use other types of disks.

"No bootable device -- insert boot disk and press any key" is a message from the Boot Camp CSM.

The thread at https://forums.macrumors.com/thread...run-within-macos-using-e-g-parallels.2346647/ mentions a script "DumpVols.sh" that can be used to collect info about the disks. It will should the contents of all the MBRs to see which have valid boot code.

 

[piller97]

I thought you would want to use the disk in an external enclosure for both the cMP and the rMBP.

Sorry, in the cMP application its located in one of the internal drive bays. Its only mounted externally when trying to connect it to laptops.

FireWire? Is the drive in a FireWire enclosure or a USB enclosure?

Again, sorry. Referring to the icons displayed I would referring to this 'firewire icon' something I'm accustomed to seeing with non bootable drives like regular external hard drives, as opposed to bootable drives where I'd see this.

I don't know what you mean by Bootcamp and Bios. Where do you see those?

"Windows" is the name shown in the Apple Startup Manager (when you hold option key at boot) for any disk that contains an MBR with boot code.

When entering startup manager on the cMP I'm presented with all the drives installed in internal bays(assuming no external drives).
For the disk on which the windows installation in question is installed this presents as two drives.
1: the windows drive named Bootcamp, which is show as "Windows[EDIT: originally referred to as Bootcamp]"
2: What I assume to be the corresponding bios(partition?), which shows as "EFI Boot[EDIT: originally referred to as Bios]"

The thread at https://forums.macrumors.com/thread...run-within-macos-using-e-g-parallels.2346647/ mentions a script "DumpVols.sh" that can be used to collect info about the disks. It will should the contents of all the MBRs to see which have valid boot code.

I will have to read further, but would this suggest that this drives boots on a cMP (installed internally) but fails to boot on other (laptop) legacy compatible macs due to the install location.

EDIT:
It would appear my memory has failed me on a couple things.

Here is a picture of startup manager on the cMP.

Drive 1:The main MacOS drive on the cMP
Drive 2: A drive from one of my old macs that is portioned with bootcamp, however is in practice not usable. The mac side has some files I want to keep. Is installed in the cMP only so I don't loose it.
Drive 3: The windows drive in question.
**Drive 3 also highlights what I mean by 'Firewire' drive VS bootable drive

I have to appologize, for some reason I recalled the windows drive as being two portions: 'Bootcamp' and 'bios'
However they acutually display as 'Windows' and 'EFI Boot'.
I've corrected references.

******
I realize the fact that its called "EFI Boot" may be confusing..........
Considering it doesn't function on macs that should be compatible with EFI drives,
and what Ive seen on the windows side indicating its a legacy install.
I think it should be safe to say it is indeed a legacy bios install

 

[joevt]

Sorry, in the cMP application its located in one of the internal drive bays. Its only mounted externally when trying to connect it to laptops.

Ok. Internal drive bay is a supported legacy boot option.

Again, sorry. Referring to the icons displayed I would referring to this 'firewire icon' something I'm accustomed to seeing with non bootable drives like regular external hard drives

That's the USB trident icon. The FireWire logo is different.
https://en.wikipedia.org/wiki/USB
https://en.wikipedia.org/wiki/IEEE_1394

as opposed to bootable drives where I'd see this.

External drives are bootable if they are macOS or Linux. Windows has ways to boot external USB but has different behaviour than normal Windows (though maybe this can be modified).

I will have to read further, but would this suggest that this drives boots on a cMP (installed internally) but fails to boot on other (laptop) legacy compatible macs due to the install location.

Not enough info. Generally, for Macs with legacy bios boot, the drive needs to be internal or DVD. Not sure about USB.

When entering startup manager on the cMP I'm presented with all the drives installed in internal bays(assuming no external drives).
For the disk on which the windows installation in question is installed this presents as two drives.
1: the windows drive named Bootcamp, which is show as "Windows[EDIT: originally referred to as Bootcamp]"
2: What I assume to be the corresponding bios(partition?), which shows as "EFI Boot[EDIT: originally referred to as Bios]"

Here is a picture of startup manager on the cMP.
View attachment 2018915
Drive 1:The main MacOS drive on the cMP
Drive 2: A drive from one of my old macs that is portioned with bootcamp, however is in practice not usable. The mac side has some files I want to keep. Is installed in the cMP only so I don't loose it.
Drive 3: The windows drive in question.
**Drive 3 also highlights what I mean by 'Firewire' drive VS bootable drive

I have to appologize, for some reason I recalled the windows drive as being two portions: 'Bootcamp' and 'bios'
However they acutually display as 'Windows' and 'EFI Boot'.
I've corrected references.

******
I realize the fact that its called "EFI Boot" may be confusing..........
Considering it doesn't function on macs that should be compatible with EFI drives,
and what Ive seen on the windows side indicating its a legacy install.
I think it should be safe to say it is indeed a legacy bios install

EFI Boot should not exist unless there's a bootx64.efi file in a /EFI/boot folder on a FAT or HFS partition. It would be interesting to find that.
The fact it has a USB icon means it's an external drive but you said all the drives are internal?

Use the dumpvols.sh script to get all the info for all the drives.
Mount all the EFI partitions to see if any have a bootx64.efi file.

 

[piller97]

That's the USB trident icon. The FireWire logo is different.
https://en.wikipedia.org/wiki/USB
https://en.wikipedia.org/wiki/IEEE_1394

OH BOY!......Ok now I know I've not been getting enough sleep of late 😅🤦‍♂️...... of course you are correct.

Clocking out, back in the morning with results of 'dumpvols.sh'