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Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
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hi guys,

I'm at a point where i want to install a modded windows 11 that bypasses the TPM. Im aware that windows 11 on the mac pro 2009 is not officially supported but id want give it a shot. i tried going through the bootcamp installer and even used a windows 7 iso file which bootcamp couldn't detect, overall its a pit of endless problems. I'm now trying to boot through the windows usb installer which wont appear in the boot menu. strange enough, I've installed mac os through usb without any issues, not sure why it wouldn't do so with windows. I've googled around and noticed that people had to use DVD's to install windows, so I'm not sure if booting via DVD's is the only way to boot into the windows installer. What do you guys suggest?
 

Macschrauber

macrumors 68030
Dec 27, 2015
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be very careful installing over USB.

you might get windows certificates due to booting the USB Stick in the firmware what can botch it the long run. (without OpenCore or RefindPlus firmware protection)

install it via a booted DVD or via the bare metal method with a "real" virtual disc via a virtual machine like @Dayo described.

You should check for certificates if you have booted the USB installer. My dumper can do this in one turnaround - plus some other checks and makes a useful firmware backup.

 
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Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
18
0
be very careful installing over USB.

you might get windows certificates due to booting the USB Stick in the firmware what can botch it the long run. (without OpenCore or RefindPlus firmware protection)

install it via a booted DVD or via the bare metal method with a "real" virtual disc via a virtual machine like @Dayo described.

You should check for certificates if you have booted the USB installer. My dumper can do this in one turnaround - plus some other checks and makes a useful firmware backup.

so im better off installing windows via DVD and avoid the hassles?
 

Macschrauber

macrumors 68030
Dec 27, 2015
2,800
1,381
Germany
so im better off installing windows via DVD and avoid the hassles?

if you want to run an unsupported Mac OS (like Catalina, Big Sur, Monterey) you will need OpenCore for it. If so you can go the OpenCore protected way of an UEFI Windows installation.

If you want to run just Windows and/or a supported Mac OS you should not run the USB Windows installer.

If you booted the thumb drive and you got a Windows Installer GUI there is a high chance that you already botched the nvram with windows certificates. What can brick the machine if there are additional glitches in the NVRAM. If so, better use my tool (or other methods) to check if there are Windows certificates.

To remove the certificates you can flash your firmware backup (guess you have none) or ask for a firmware reconstruction.

The first purpose I made the tool was to set everyone able to have a firmware backup. Of course, this baby has grown and gained functions over time...
 

Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
18
0
So far I’ve burned a windows copy on a dvd. Tried installing it and no luck. Now im facing a situation where the system won’t respond to the “alt option” key, pram reset and other functions. The system attempts to directly boot into the dvd. Ive connected the mac os installer but didn’t load and tried booting into windows, pulled the hard drive out, removed the disc, disconnected the disc reader along with the mac os installer and it magically still tries to boot into the dvd. I first get a grey screen then a black screen with white text saying that there isnt a bootable media, the kind where you’d see on a pc with no OS. Booting into the dvd will now simply get me stuck in the windows logo. Any ideas?
 

tsialex

Contributor
Jun 13, 2016
13,065
13,275
So far I’ve burned a windows copy on a dvd. Tried installing it and no luck. Now im facing a situation where the system won’t respond to the “alt option” key, pram reset and other functions. The system attempts to directly boot into the dvd. Ive connected the mac os installer but didn’t load and tried booting into windows, pulled the hard drive out, removed the disc, disconnected the disc reader along with the mac os installer and it magically still tries to boot into the dvd. I first get a grey screen then a black screen with white text saying that there isnt a bootable media, the kind where you’d see on a pc with no OS. Booting into the dvd will now simply get me stuck in the windows logo. Any ideas?
You probably corrupted the NVRAM volume, your only way to get out of this boot loop is with a deep NVRAM reset.

Install a wired keyboard that works for multiple NVRAM resets, press and keep pressed CMD-Option-P-R until you hear the 5th chime. Yes, you will need to reset the NVRAM consecutively at least 4 times.

Not all wired keyboards can do this, a lot of very common Microsoft and Logitech keyboards only work for the 1st NVRAM reset - Microsoft Wired 600 is one very common keyboard that can't do it.

No wireless keyboard (even Apple) can do it.
 

Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
18
0
You probably corrupted the NVRAM volume, your only way to get out of this boot loop is with a deep NVRAM reset.

Install a wired keyboard that works for multiple NVRAM resets, press and keep pressed CMD-Option-P-R until you hear the 5th chime. Yes, you will need to reset the NVRAM consecutively at least 4 times.

Not all wired keyboards can do this, a lot of very common Microsoft and Logitech keyboards only work for the 1st NVRAM reset - Microsoft Wired 600 is one very common keyboard that can't do it.

No wireless keyboard (even Apple) can do it.

Would it still count even if I don’t hear the chime twice? All i get whenever i startup the computer is a blank grey screen till the “no media” black screen message appears regardless the command functions i press.

I also have a full size wired aluminum apple keyboard, would that work for this process?
 

tsialex

Contributor
Jun 13, 2016
13,065
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Would it still count even if I don’t hear the chime twice? All i get whenever i startup the computer is a blank grey screen till the “no media” black screen message appears regardless the command functions i press.

You press the power on button and right away start pressing the CMD-Option-P-R keys and don't let go until the 5th chime. If you can't get it done, you have a real major problem, unfortunately.

I also have a full size wired aluminum apple keyboard, would that work for this process?

If it's not one from 2007 to 2010ish that needs a firmware update, if you used it before the firmware was probably updated already (this is a problem just with NOS keyboards), should work perfectly.
 

Soba

macrumors 6502
May 28, 2003
450
700
Rochester, NY
Would it still count even if I don’t hear the chime twice? All i get whenever i startup the computer is a blank grey screen till the “no media” black screen message appears regardless the command functions i press.

I also have a full size wired aluminum apple keyboard, would that work for this process?

My only other suggestion is to make sure your keyboard is plugged directly into one of the Mac Pro's built-in USB ports (you can use a port on the front of the case for simplicity) and not into a hub or any other device.

From your post, it sounds like you're only hearing the chime once when you first power up the Mac. If this is incorrect and you're hearing it twice (but no more), note that sometimes it helps to briefly release the keys (less than 1 second) each time the Mac reboots and then immediately re-press the keys before the chime sounds to get the Mac to re-recognize the key presses.
 

Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
18
0
Looks like the boot problem got fixed, well done guys.

I have another question in regards with windows, is there a specific workaround to install windows 10 or 11 on a firmware MP51.0089.B00 or any firmware other than 144 or is 144.0.0.0.0 forcefully required? Ive tried many workarounds but they all result into various problems and errors that prevent me from installing 😫
 
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Soba

macrumors 6502
May 28, 2003
450
700
Rochester, NY
Looks like the boot problem got fixed, well done guys.

I have another question in regards with windows, is there a specific workaround to install windows 10 or 11 on a firmware MP51.0089.B00 or any firmware other than 144 or is 144.0.0.0.0 forcefully required? Ive tried many workarounds but they all result into various problems and errors that prevent me from installing 😫
Is there a specific reason you don't want version 144.0.0.0.0?

I've never had a problem installing Windows 10 from DVD on my 5,1 and this was consistent with many different Windows 10 releases. Just insert the DVD, boot from it, and the installer runs just as it would on any PC. If this does not work for you, then please post again with details of what happens.

I did this not long ago and it works as expected with current releases of Windows 10. There was a very long delay in booting on my 5,1 where I had the spinning Windows logo for about 20 minutes, but the installer eventually loaded and Windows ran perfectly once installed.

Also, to emphasize what's been said in earlier posts, you said you already booted the Windows installer from a USB drive. This is bad, and it's possible this has caused a serious firmware problem with Windows boot certificates, which is a time bomb and can easily result in your system being permanently bricked. If this occurs, the system is dead and cannot be repaired except through major effort.

You should diagnose your firmware before doing anything else. Follow the link that @Macschrauber posted above, run the diagnostic tool, and make sure your firmware does not have any certificates from Microsoft.
 
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Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
18
0
Is there a specific reason you don't want version 144.0.0.0.0?

I've never had a problem installing Windows 10 from DVD on my 5,1 and this was consistent with many different Windows 10 releases. Just insert the DVD, boot from it, and the installer runs just as it would on any PC. If this does not work for you, then please post again with details of what happens.

I did this not long ago and it works as expected with current releases of Windows 10. There was a very long delay in booting on my 5,1 where I had the spinning Windows logo for about 20 minutes, but the installer eventually loaded and Windows ran perfectly once installed.

Also, to emphasize what's been said in earlier posts, you said you already booted the Windows installer from a USB drive. This is bad, and it's possible this has caused a serious firmware problem with Windows boot certificates, which is a time bomb and can easily result in your system being permanently bricked. If this occurs, the system is dead and cannot be repaired except through major effort.

You should diagnose your firmware before doing anything else. Follow the link that @Macschrauber posted above, run the diagnostic tool, and make sure your firmware does not have any certificates from Microsoft.

I'd like to upgrade the firmware to the latest, the problem is that i dont have a metal supported graphics and am looking workarounds to get windows installed without spending another fortune on a metal gpu

I made a windows 11 installation dvd and booted off of that, i would originally get the gpt format error when making a ms dos fat partition on mac os. Id then wipe the drive entirely and solely install windows 11, everything goes smooth till the installation process gets interrupted with 0x800705aa. Installing windows 8 worked but upgrading the os to w10 tells me to open the setup from elsewhere, did workarounds, didn’t work. Got other iso copies and the results were the same. W11 couldn’t get any worse with other variant problems.

In your case, did you update your firmware to 144 before going through this process?
 

Soba

macrumors 6502
May 28, 2003
450
700
Rochester, NY
I'd like to upgrade the firmware to the latest, the problem is that i dont have a metal supported graphics and am looking workarounds to get windows installed without spending another fortune on a metal gpu

[…]

In your case, did you update your firmware to 144 before going through this process?

Not in all cases. I've installed Windows 10 (and Windows 7, before 10 was released) on my 5,1 a number of times; I used to be involved in software testing, so I needed to rebuild my Windows environment from time to time. That includes many installations long before BootROM 144.0.0.0.0 was released.

If you don't want to run Mojave, perhaps you could borrow a Metal GPU just to update your BootROM. Or, you could buy an inexpensive Metal GPU. Failing that, it might be possible to pay for a BootROM reconstruction to bypass this requirement if you're not planning to run Mojave.

I believe that 4,1 -> 5,1 Mac Pro's are highly susceptible to BootROM corruption and bricking in any event, so you might want to look into a BootROM reconstruction service. Others who are more knowledgeable on this can help you better than I can.

I made a windows 11 installation dvd and booted off of that, i would originally get the gpt format error when making a ms dos fat partition on mac os. Id then wipe the drive entirely and solely install windows 11, everything goes smooth till the installation process gets interrupted with 0x800705aa. Installing windows 8 worked but upgrading the os to w10 tells me to open the setup from elsewhere, did workarounds, didn’t work. Got other iso copies and the results were the same. W11 couldn’t get any worse with other variant problems.

I recommend using Windows 10 for now just to get your machine to a usable state. It doesn't need any special hacking to install. It does require a few extra steps to get the Boot Camp drivers and a working Windows Boot Camp Control Panel installed because Apple never released native Windows 10 drivers for the 5,1 but this is not difficult and is documented in other threads here on the forum.

You said you "got other ISO copies" which makes me curious where you got them from. Make sure you're using only the latest ISO downloaded directly from Microsoft then burn it to DVD and you should be able to boot and do a clean install with no trouble.

And not meaning to sound like a nag, but please check your BootROM for Microsoft boot certificates before trying any further installation or upgrade activities. If your system gets bricked because of corruption, this whole discussion will be moot.
 
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Microsoft Corporation

macrumors newbie
Original poster
May 16, 2018
18
0
Not in all cases. I've installed Windows 10 (and Windows 7, before 10 was released) on my 5,1 a number of times; I used to be involved in software testing, so I needed to rebuild my Windows environment from time to time. That includes many installations long before BootROM 144.0.0.0.0 was released.

If you don't want to run Mojave, perhaps you could borrow a Metal GPU just to update your BootROM. Or, you could buy an inexpensive Metal GPU. Failing that, it might be possible to pay for a BootROM reconstruction to bypass this requirement if you're not planning to run Mojave.

I believe that 4,1 -> 5,1 Mac Pro's are highly susceptible to BootROM corruption and bricking in any event, so you might want to look into a BootROM reconstruction service. Others who are more knowledgeable on this can help you better than I can.



I recommend using Windows 10 for now just to get your machine to a usable state. It doesn't need any special hacking to install. It does require a few extra steps to get the Boot Camp drivers and a working Windows Boot Camp Control Panel installed because Apple never released native Windows 10 drivers for the 5,1 but this is not difficult and is documented in other threads here on the forum.

You said you "got other ISO copies" which makes me curious where you got them from. Make sure you're using only the latest ISO downloaded directly from Microsoft then burn it to DVD and you should be able to boot and do a clean install with no trouble.

And not meaning to sound like a nag, but please check your BootROM for Microsoft boot certificates before trying any further installation or upgrade activities. If your system gets bricked because of corruption, this whole discussion will be moot.
How can i check for bootrom issues and how would I identify errors? If i find any issues, will i be able to fix it?
 

tsialex

Contributor
Jun 13, 2016
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How can i check for bootrom issues and how would I identify errors? If i find any issues, will i be able to fix it?
A cross-flashed early-2009 Mac Pro is already problematic from the get go, since the factory BootROM image (the MP4,1 firmware) have a NVRAM volume with only one VSS store and a fully working FWB store, while the cross flashed MP5,1 EFI firmware expects a NVRAM volume with two VSS stores and a disabled FWB store. There are several other minor differences between the early-2009 and mid-2010 firmwares that I've explained on the main BootROM thread, if the topic interests you.

Unfortunately these differences overtime slowly corrupt the NVRAM volume and when the NVRAM finally auto destructs itself, you have a bricked Mac Pro backplane and that's the main reason why so much early-2009 Mac Pros stop working with a perfect hardware and a dead firmware.

Btw, with Microsoft Windows UEFI SecureBoot signing, long story short, the incompatibilities are greatly exacerbated and a process that would take years for the BootROM corruption to finally brick the BootROM, unfortunately can happen in months or even weeks.

While you can check if your BootROM have Microsoft Windows UEFI SecureBoot signing yourself with a binwalk or the @Macschrauber tool linked here before, you can't clean up the SecureBoot signing or repair the cross-flashing mess yourself, you gonna need a BootROM reconstruction service.
 
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ayr_07

macrumors newbie
Oct 26, 2022
9
2
A cross-flashed early-2009 Mac Pro is already problematic from the get go, since the factory BootROM image (the MP4,1 firmware) have a NVRAM volume with only one VSS store and a fully working FWB store, while the cross flashed MP5,1 EFI firmware expects a NVRAM volume with two VSS stores and a disabled FWB store. There are several other minor differences between the early-2009 and mid-2010 firmwares that I've explained on the main BootROM thread, if the topic interests you.

Unfortunately these differences overtime slowly corrupt the NVRAM volume and when the NVRAM finally auto destructs itself, you have a bricked Mac Pro backplane and that's the main reason why so much early-2009 Mac Pros stop working with a perfect hardware and a dead firmware.
Hi, I am new to this forum, so pardon any stupid questions. I have 4,1 Mac Pro in which I was running Open Core very comfortably from last 8 months with an RX 580. During the last couple of months I was able to boot the Mac Pro only after doing a PRAM reset at every boot. And now yesterday, it just switched off randomly while browsing. I am not able to boot it up since then, it starts but no chime and no display. This is what I have tried:

1. Removed all secondary drives and tried resetting PRAM during boot
2. Removing all the drives and the RX 580, reinstalled the original graphics card (it is in working condition) that came with the Mac Pro and no boot drive. Still no chime and no display.
3. Tried a different monitor and ports at the graphics card.

I am up for ideas to resolve this.

And @tsialex - I have always appreciated the insights you have given in this forum especially regarding the Mac Pro. Your inputs will also help. I only suspect based on what I have read, but is the backplane gone for good or there is hope?
 

tsialex

Contributor
Jun 13, 2016
13,065
13,275
Seems you have a brick or a dead backplane. When you press DIAG button, which LEDs are lit?

Things to do to make it easier for you to diagnose your Mac Pro:

  1. Double check the voltage of the BR2032 RTC battery with a voltmeter/multimeter, if the battery is below 3.00V you need to replace it. When the RTC battery have a low voltage, the RTC time related counters will be stuck or with invalid values and the Mac Pro behaves completely crazily - it's the first thing you should check.
  2. After checking the RTC battery voltage, remove all DIMMs installed except one that should be the DIMM installed in the DIMM slot 1, this makes it easier for the PEI initialize the system with a corrupt NVRAM or defective SPI flash memory.
  3. If you have a defective SPI flash memory with dead NAND cells where the NVRAM volume is stored inside the Mac Pro BootROM, disconnect the mains power cable from the PSU, remove the BR2032 RTC battery, wait at least a minute, connect the mains power cable to the PSU again, power on and check if you can boot - with the battery removed the PEI will bypass the NVRAM VSS stores and power on with a fail safe mode. You can't work with the Mac Pro like that, but you will be certain about what is the defect.
  4. Defective SATA devices can also make the backplane behave like a brick, so remove everything from your Mac Pro while you are trying to diagnose it. You don't need to remove the DVD, but disconnect the cable from it.
 
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ayr_07

macrumors newbie
Oct 26, 2022
9
2
Seems you have a brick or a dead backplane. When you press DIAG button, which LEDs are lit?

Things to do to make it easier for you to diagnose your Mac Pro:

  1. Double check the voltage of the BR2032 RTC battery with a voltmeter/multimeter, if the battery is below 3.00V you need to replace it. When the RTC battery have a low voltage, the RTC time related counters will be stuck or with invalid values and the Mac Pro behaves completely crazily - it's the first thing you should check.
  2. After checking the RTC battery voltage, remove all DIMMs installed except one that should be the DIMM installed in the DIMM slot 1, this makes it easier for the PEI initialize the system with a corrupt NVRAM or defective SPI flash memory.
  3. If you have a defective SPI flash memory with dead NAND cells where the NVRAM volume is stored inside the Mac Pro BootROM, disconnect the mains power cable from the PSU, remove the BR2032 RTC battery, wait at least a minute, connect the mains power cable to the PSU again, power on and check if you can boot - with the battery removed the PEI will bypass the NVRAM VSS stores and power on with a fail safe mode. You can't work with the Mac Pro like that, but you will be certain about what is the defect.
  4. Defective SATA devices can also make the backplane behave like a brick, so remove everything from your Mac Pro while you are trying to diagnose it. You don't need to remove the DVD, but disconnect the cable from it.
Thanks @tsialex for your suggestions. Here is the summary of the output when I tried them all but with no success:

When I press the DIAG button, the LEDs as per the pic attached light up. Is something wrong in what the LEDs are showing?

  1. I checked the voltage of the RTC battery, it is exactly 3.00 V, so that rules out issues due to the battery I guess.
  2. I kept only the DIMM 1 with 1 RAM stick and unpopulated the remaining 7 slots. When I switch on, I see no difference, still teh same symptoms.
  3. I unplugged the power to the PSU and removed the RTC battery, left it for a couple of minutes and powered on but still no display and the Mac stays on.
  4. I also tried the same by disconnecting all the drives and the dvd drive, but the same outcome.
So does this mean that the backplane is dead and cannot be revived? Please suggest what can I do to make it up and running again?

Thanks.
 

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tsialex

Contributor
Jun 13, 2016
13,065
13,275
Thanks @tsialex for your suggestions. Here is the summary of the output when I tried them all but with no success:

When I press the DIAG button, the LEDs as per the pic attached light up. Is something wrong in what the LEDs are showing?

  1. I checked the voltage of the RTC battery, it is exactly 3.00 V, so that rules out issues due to the battery I guess.
  2. I kept only the DIMM 1 with 1 RAM stick and unpopulated the remaining 7 slots. When I switch on, I see no difference, still teh same symptoms.
  3. I unplugged the power to the PSU and removed the RTC battery, left it for a couple of minutes and powered on but still no display and the Mac stays on.
  4. I also tried the same by disconnecting all the drives and the dvd drive, but the same outcome.
So does this mean that the backplane is dead and cannot be revived? Please suggest what can I do to make it up and running again?

Thanks.
EFI_DONE is lit. Can you desolder the 8-pin SOP SPI flash and reprogram it?
 

ayr_07

macrumors newbie
Oct 26, 2022
9
2
EFI_DONE is lit. Can you desolder the 8-pin SOP SPI flash and reprogram it?
I am total noob when it comes to desolder and solder. I know someone who is an expert with the soldering part on electronic boards, and might have the tools to reprogram as well. Is there any guide on how to do this, so that I can check with my guy? Worst case if the programming is not possible, does someone program a fresh 8-pin SOP SPI and sell it, maybe I can buy and get it soldered by my guy, only if that's possible logically?
 

tsialex

Contributor
Jun 13, 2016
13,065
13,275
I am total noob when it comes to desolder and solder. I know someone who is an expert with the soldering part on electronic boards, and might have the tools to reprogram as well. Is there any guide on how to do this, so that I can check with my guy? Worst case if the programming is not possible, does someone program a fresh 8-pin SOP SPI and sell it, maybe I can buy and get it soldered by my guy, only if that's possible logically?
Please read the first post of the thread below:

 

ayr_07

macrumors newbie
Oct 26, 2022
9
2
Please read the first post of the thread below:

Thanks. I read the first post and it seems that getting another backplane is the cheapest way to sort the issue. From what I have understood, the problem I faced currently happened due the bootROM being corrupted and looks like it is expected to happen over time when Opencore is used to run unsupported OS on crossflashed 4,1 ROM to 5, 1. Is my understanding correct?

If the answer to my doubt is yes, won't the next backplane I procure have the same issues after 8-10 months? Or maybe I misunderstood something. Please clarify. Thanks.
 

tsialex

Contributor
Jun 13, 2016
13,065
13,275
Thanks. I read the first post and it seems that getting another backplane is the cheapest way to sort the issue. From what I have understood, the problem I faced currently happened due the bootROM being corrupted and looks like it is expected to happen over time when Opencore is used to run unsupported OS on crossflashed 4,1 ROM to 5, 1. Is my understanding correct?
It's worse with cross-flashed early-2009 Mac Pros, but it can happen even with real mid-2012s. It's not OpenCore related, the culprit are Software Updates staging for macOS releases that requires Signed System Volume, SSV - Big Sur on-wards.

Software Updates with SSV requires 20KB or more of variables to be staged inside the main VSS store and now Apple is issuing almost monthly Software Updates, a perfect storm.

If the answer to my doubt is yes, won't the next backplane I procure have the same issues after 8-10 months? Or maybe I misunderstood something. Please clarify. Thanks.

Yes, will happen again. The way to circumvent it is to repair the cross-flashing issues with a BootROM reconstruction service (so you now are equivalent of a mid-2012 with no issues) and re-flash the never booted reconstructed BootROM image from time to time. I do it in 90 days intervals.
 

izbits

macrumors newbie
Oct 21, 2022
3
7
It's worse with cross-flashed early-2009 Mac Pros, but it can happen even with real mid-2012s. It's not OpenCore related, the culprit are Software Updates staging for macOS releases that requires Signed System Volume, SSV - Big Sur on-wards.

Software Updates with SSV requires 20KB or more of variables to be staged inside the main VSS store and now Apple is issuing almost monthly Software Updates, a perfect storm.



Yes, will happen again. The way to circumvent it is to repair the cross-flashing issues with a BootROM reconstruction service (so you now are equivalent of a mid-2012 with no issues) and re-flash the never booted reconstructed BootROM image from time to time. I do it in 90 days intervals.
Will a cross flashed 2009 work fine if its only running Mojave?

i've just picked up an old 4.1 and performed the 5.1 flash, i downloaded the cMP rom dump tool and it says everything is fine. i plan to install windows, firstly using boot camp and then i'll look into other options if i want more performance later, i also have the windows iso ready for the install.
 

tsialex

Contributor
Jun 13, 2016
13,065
13,275
Will a cross flashed 2009 work fine if its only running Mojave?

For a series of reasons that I've explained in the past, all MacPro5,1 BootROMs will fail sometime in the future while cross-flashed early-2009 will fail a lot faster, it's inevitable and you have a Mac Pro with 12 or 13 years since it came out of the factory.

Snow Leopard/Lion use/interact a lot less with the NVRAM than Mojave and newer unsupported releases, but even MacPros that never were upgraded from 10.6 still fail.

i've just picked up an old 4.1 and performed the 5.1 flash, i downloaded the cMP rom dump tool and it says everything is fine. i plan to install windows, firstly using boot camp and then i'll look into other options if i want more performance later, i also have the windows iso ready for the install.

You can be pro-active and repair the issues now or reactive and repair when it fails. Later the cost and downtime will be greater.
 
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