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Recovery Partition not require EFI GPU anymore

h9826790

h9826790

macrumors P6
Original poster
Apr 3, 2014
16,666
8,594
Hong Kong
As some RX480 users pointed out that they can access the recovery partition without any EFI. I jsut tested it with my 7950. I booted my Mac with the non EFI VBIOS, hold Command + R, and I can confirm that I can use recovery partition without any issue.

TBH, I couldn't remember if I try this before Sierra. I don't know when this function exist. Or, I simply assume the recovery partition won't work without EFI.

If my assumption is correct. That means any OOTB GPU, even not fully accelerated card, as long as it can display something in Sierra, the recovery partition is accessible.

I assume the recovery partition can only load the Apple driver, however, if anyone have the non EFI Maxwell card, you may test if the recovery partition actually accessible for you in Sierra now.
[doublepost=1475478415][/doublepost]Anyway, it seems Apple finally moving away from their legacy EFI.

A flashed GPU now basically only provide
1) the boot manager
2) a precise ident in the system info
3) may be still a requirement for the HDMI Audio to work properly

Function 1 is pretty redundant, because we can easily pick the boot partition inside the OS, or use key combo during boot.
Function 2 is purely cosmetic, completely an extra bonus without any real impact on any operation.
Function 3 is still an unknown.


And now
a) Recovery partition can work with PC card
b) the apple logo (loading bar) may appear during boot

These 2 functions usually not doing anything in daily ops. However, now we can disable SIP with non EFI GPU. And we can see if the loading bar stuck during boot. Which are useful when something went wrong.
 
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h9826790 said:
As some RX480 users pointed out that they can access the recovery partition without any EFI. I jsut tested it with my 7950. I booted my Mac with the non EFI VBIOS, hold Command + R, and I can confirm that I can use recovery partition without any issue.

TBH, I couldn't remember if I try this before Sierra. I don't know when this function exist. Or, I simply assume the recovery partition won't work without EFI.

If my assumption is correct. That means any OOTB GPU, even not fully accelerated card, as long as it can display something in Sierra, the recovery partition is accessible.

I assume the recovery partition can only load the Apple driver, however, if anyone have the non EFI Maxwell card, you may test if the recovery partition actually accessible for you in Sierra now.
[doublepost=1475478415][/doublepost]Anyway, it seems Apple finally moving away from their legacy EFI.

A flashed GPU now basically only provide
1) the boot manager
2) a precise ident in the system info
3) may be still a requirement for the HDMI Audio to work properly

Function 1 is pretty redundant, because we can easily pick the boot partition inside the OS, or use key combo during boot.
Function 2 is purely cosmetic, completely an extra bonus without any real impact on any operation.
Function 3 is still an unknown.


And now
a) Recovery partition can work with PC card
b) the apple logo (loading bar) may appear during boot

These 2 functions usually not doing anything in daily ops. However, now we can disable SIP with non EFI GPU. And we can see if the loading bar stuck during boot. Which are useful when something went wrong.
Click to expand...

The recovery partition on my machine would not provide a GUI using a flashed 980Ti, even though most of the boot process would be displayed. This changed around 10.11.5 when the recovery partition was updated. It worked as normal.

I did notice that 10.12 "corrected" the boot progress bar. Using 10.11, the bar would appear normal, and at the last part of the boot process before the login screen, it would appear in the lower left of the screen, with the remainder of the screen being black. Now, it looks completely normal like a factory Apple video card.
 
One thing comes to mind. All this is done for... external GPU enclosures.
 
monkeybagel said:
The recovery partition on my machine would not provide a GUI using a flashed 980Ti, even though most of the boot process would be displayed. This changed around 10.11.5 when the recovery partition was updated. It worked as normal.

I did notice that 10.12 "corrected" the boot progress bar. Using 10.11, the bar would appear normal, and at the last part of the boot process before the login screen, it would appear in the lower left of the screen, with the remainder of the screen being black. Now, it looks completely normal like a factory Apple video card.
Click to expand...

Thanks for the test, that's way beyond my imagination. Apple actually intentionally kill the EFI support in recovery partition, but only support the GPU that can be used with Apple driver.
[doublepost=1475503687][/doublepost]
koyoot said:
One thing comes to mind. All this is done for... external GPU enclosures.
Click to expand...

May be you are right, but not very Apple way, even though MacOS support eGPU, most likely Apple want to sell their own Mac version eGPU. And now is the other way around, any supported GPU without EFI will work fine.
 
It's unrealistic to think Apple will ever provide support for BYOGPU. Polaris 10 chipset inside the new 5K display is the best we'll get.

I'm not buying one but many will because it's a simple solution for Macs without dGPU. My hope is that the community will be able to replicate what Apple builds in this setup for our DIY eGPU.
 
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