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MacProXUser

macrumors newbie
Original poster
Dec 19, 2020
4
0
Hi everyone,

I'm sorry to start a new thread here about that but can't find the one I followed... it was a 300+ pages one about installing windows on a Mac Pro 5,1. it's been months I haven't been here and every threads on this subject seem to be talking about open core (with is not the method I used)

Anyway here's my problem :

I've installed 3 different SSD's on a Mac Pro 4,1 flashed to 5,1.
On each, there's a different system : Mountain lion, Mojave, Windows 10 (in legacy mode)
I need to say that when I'm working on a system everything is fluid and flawless
BUT
I can't reach the boot screen when holding the option key at the startup

It "feels" like a windows problem...

1# If I hold the option key, after the chime, the fans go slightly up (around 20-25% speed) and black screen
2# If I select Windows from mountain lion startup disk selection, restart is done on Windows
3# if I select Mountain lion or Mojave from boot camp on windows, it restarts on Windows at a 80% frequency
4# If I reset the pram (3 chimes) and hold option key, fans go slightly up (around 20-25% speed) and a black screen
5# After a reset of the pram without the windows ssd connected, it starts on mountain lion. If I shutdown and start again while holding the option key, I get the boot screen selector once ! If I repeat this procedure, then black screen, fans up...

I've read about the sudo nvram manufacturing-enter-picker=true command... Do you think it will help me ?
Is there something else I need to check ? (I've installed windows by needs but I'm the worst noob ever on this os !)

Thanks in advance for your kindness
 

zedex

macrumors 6502
Oct 21, 2018
312
134
Perth, WA
Bootpicker is only displayed universally (regardless of GPU) if you are running Opencore. If you're not using OC, like me, then you won't get a bootscreen on a standard R9 280 (unless you have correctly flashed your card with the GPU ROM that originally shipped with the Radeon HD 7950 Mac Edition).
 

Soba

macrumors 6502
May 28, 2003
450
700
Rochester, NY
If I shutdown and start again while holding the option key, I get the boot screen selector once !

I'm curious why this works under this circumstance at all with your graphics card, but perhaps someone more knowledgeable can explain.

Small note, though this is unlikely to help your problem—a full NVRAM reset is 4 chimes and not 3, like so:

Chime -> Cmd+Opt+P+R -> Mac restarts
Chime -> Cmd+Opt+P+R -> Mac restarts
Chime -> Cmd+Opt+P+R -> Mac restarts
Chime -> System boots up
 

MacProXUser

macrumors newbie
Original poster
Dec 19, 2020
4
0
Bootpicker is only displayed universally (regardless of GPU) if you are running Opencore. If you're not using OC, like me, then you won't get a bootscreen on a standard R9 280 (unless you have correctly flashed your card with the GPU ROM that originally shipped with the Radeon HD 7950 Mac Edition).
I said that my card is seen as R9 280, because it is a hd 7950 indeed.

Your reply make me ask two new questions.

1) if this shouldn’t work, why can I reach the bootpicker sometimes ?
2) Do you mean that I need to install oc to get rid of my problems ?

And once again, will the “sudo nvram manufacturing-enter-picker=true” command help to solve the problem ?

Thanks for your help
 

MacProXUser

macrumors newbie
Original poster
Dec 19, 2020
4
0
I'm curious why this works under this circumstance at all with your graphics card, but perhaps someone more knowledgeable can explain.

Small note, though this is unlikely to help your problem—a full NVRAM reset is 4 chimes and not 3, like so:

Chime -> Cmd+Opt+P+R -> Mac restarts
Chime -> Cmd+Opt+P+R -> Mac restarts
Chime -> Cmd+Opt+P+R -> Mac restarts
Chime -> System boots up
I get the bootscreen on other situations but not enough predictable to make any guess…

And yes, the nvram reset is done after 3 chimes + the starting chime ;-)
 

KeesMacPro

macrumors 65816
Nov 7, 2019
1,453
595
said that my card is seen as R9 280, because it is a hd 7950 indeed.

Your reply make me ask two new questions.

1) if this shouldn’t work, why can I reach the bootpicker sometimes ?
2) Do you mean that I need to install oc to get rid of my problems ?

And once again, will the “sudo nvram manufacturing-enter-picker=true” command help to solve the problem ?
IIRC the HD7950 is Metal compatible , so works with Mojave.
If it's flashed with a Mac EFi / OEM Apple it provides a bootscreen.
Bootpicker is a term used for OpenCore installs.

Bootcamp is not supported for Mojave and up.
Nevertheless it is possible to install W10 without Bootcamp or OpenCore.
Perhaps reinstalling W10 a different way solves the issue.
For example:


Edit: the bootscreen and/or option key at start up should always work with a Mac EFI GPU regardless the OSes installed. That is for a non-OpenCore setup.
The command you mentioned is unknown to me, but the option key should work , so IMHO no need to run commands anyway , if all is working as it's supposed to be.
 
Last edited:

zedex

macrumors 6502
Oct 21, 2018
312
134
Perth, WA
1# If I hold the option key, after the chime, the fans go slightly up (around 20-25% speed) and black screen
2# If I select Windows from mountain lion startup disk selection, restart is done on Windows
3# if I select Mountain lion or Mojave from boot camp on windows, it restarts on Windows at a 80% frequency
4# If I reset the pram (3 chimes) and hold option key, fans go slightly up (around 20-25% speed) and a black screen
5# After a reset of the pram without the windows ssd connected, it starts on mountain lion. If I shutdown and start again while holding the option key, I get the boot screen selector once ! If I repeat this procedure, then black screen, fans up...

I've read about the sudo nvram manufacturing-enter-picker=true command... Do you think it will help me ?
Is there something else I need to check ? (I've installed windows by needs but I'm the worst noob ever on this os !)

I am particularly sympathetic to your frustration because I have tried to solve this puzzle myself in the past. I'll just share what I learned from my own experience..

- LEGACY MODE is the more compatible/stable of the two Windows installation options - don't make your job harder by switching to UEFI.
- I was able to get Windows working (but never with the typically strong Bootcamp integration you may have experienced on other Macs) by doing a direct/clean install of Windows 10.
- I wouldn't use 10.8 bootcamp to deploy a Win 10 installation. Windows 10 wasn't released then and could be the source of some of the issues you are experiencing. As mentioned above (kudos @KeesMacPro) 10.14 does not provide bootcamp support.
- I used 10.13 and never achieved the seamless ability to switch between volumes using (a) bootscreen selection screen or (b) syspref/startup disk selection

I wish you the best and please share any and all 'breakthroughs' in your efforts to make this multiple boot volume config work.
 
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Soba

macrumors 6502
May 28, 2003
450
700
Rochester, NY
To be clear, while the Boot Camp app will refuse to run in Mojave, it does not make much practical difference. You can still install Windows on the system by booting from the Windows install disc. Also, all the Boot Camp drivers still work; you simply need to install the drivers manually because the installers won't work on Windows 10.

You can supplement this with the Boot Camp driver package that was released for the iMac Pro, which does run on Windows 10 and gives you a working Boot Camp control panel in Windows. This post has the details, including how to download the packages you need using a utility called Brigadier:


The link above shared by KeesMacPro also explains how to do this. (Kees' link might be more up to date than the forum post.)

@MacProXUser This will probably solve your problem with Windows not rebooting into macOS when you choose the startup drive within Windows 10. Have a look at that post to install the iMac Pro Boot Camp packages for Windows 10 and see if it helps. You do not need to reinstall Windows; you can begin the procedure around step 8, which picks up after the install is complete. Note: This solution might not enable you to boot into an older version of macOS, so while this works for Mojave, you will have to try and see if it works with Mountain Lion. If you cannot reboot from Windows into Mountain Lion, you can instead reboot into Mojave, then use the Startup Disk control panel to choose your Mountain Lion drive and reboot again into that.

Unless you use a Mac-compatible GPU or a utility such as OpenCore, you will not have access to a boot screen to select the OS after the startup chime, so your system is currently working as it should (even though not having boot screens is an annoyance).
 
Last edited:
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startergo

macrumors 601
Sep 20, 2018
4,978
2,255
And once again, will the “sudo nvram manufacturing-enter-picker=true” command help to solve the problem ?
This command has the same result as holding the Option key at boot. Whatever happens when you keep Option key at boot that is what you are going to see after executing the command. To get out of that mode you have to clear NVRAM.
 

bonac

macrumors newbie
Oct 26, 2022
1
0
Well, yes and NO, this is not exactly the same:
I've been stuck for 3 days on a Imac core2Duo upgrade which messed up by install without any TimeMachine, and there was NO WAY to get the boot choice. So unable to boot on USB, unable to launche the N-1 version (obsolete).
And when I found this nvram parameter manufacturing-enter-picker this made my day, and I was able to boot from USB , run the previous installer, fix the faulty upgrade and get back the machine up & running, then upgraded to the latest supported version.
Since I have the manufacturing-enter-picker=yes, I DO have the boot disk menu choice, which I NEVER was able to have whatetever option/key stroke used.
Maybe this is a trouble related to the old iMac 8.1, probably, but öption"key was not eprferming any thing.

An THIS option: sudo nvram boot-args="-v" is also very helpful instead of sitting behind the black (white) screen for hours, not being sure of what was happening. Because it prints live all what is happening behind during boot/startup.
Regular user don't care, but when you are in some picky migrations/recover this helps, all the more you cannot do at the same time Apple+R and Apple+V ...
 
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