Setting the 'Resume from Deep Sleep' EFI Flag on a Mac

[MoonBuggy]

I've been trying to set up my (MacBook Pro) system so that I can hibernate ('deep sleep') OSX, boot into Windows, and then resume OSX from where I left off later. The first two parts work fine, but when I select 'boot into OSX' from Windows, or shut down and bring up the boot disc menu with the alt key, it does a cold boot of OSX rather than resuming the sleep image. This leads me to believe that when OSX performs a deep sleep operation, it sets a flag in EFI that tells the system to resume rather than cold boot on the next startup.

 

Anyone have any idea how I might be able to set this from Windows, so that it resumes my OSX session? Or am I completely missing the point and making false assumptions on how the sleep process is handled?

[FKA]

I've been trying to set up my (MacBook Pro) system so that I can hibernate ('deep sleep') OSX, boot into Windows, and then resume OSX from where I left off later. The first two parts work fine, but when I select 'boot into OSX' from Windows, or shut down and bring up the boot disc menu with the alt key, it does a cold boot of OSX rather than resuming the sleep image. This leads me to believe that when OSX performs a deep sleep operation, it sets a flag in EFI that tells the system to resume rather than cold boot on the next startup.

 

Anyone have any idea how I might be able to set this from Windows, so that it resumes my OSX session? Or am I completely missing the point and making false assumptions on how the sleep process is handled?

 

Got no idea if this is possible but a bloody great idea.

I presume you are using hibernation mode 1 - suspend to HDD only?

 

Hope somebody gives you an answer

 

D

[MoonBuggy]

I'm using mode 5, which is the same as 1 but for secure virtual memory.

 

I fully admit that I'm a bit new to this, but here's what I've learned so far: I've spent the afternoon going through a stack of NVRAM dumps from various situations, and I'm coming up somewhat empty. Deep sleep seems to have no visible effect on the previous NVRAM settings - the fact that it suppresses the boot chime (and disables the pre-boot button combos), however, implies that it's not just using the boot partition on the hard drive. The obvious conclusion to draw from this would be that it edits the NVRAM temporarily and then resets it as it comes out of sleep, but that wouldn't explain why setting the NVRAM boot option to windows and then hitting deep sleep still boots into windows (but without a boot chime) - if sleep mode is temporarily overwriting the contents, why does the windows boot path still remain?

 

There's also the fact that resuming from deep sleep ignores a persistent verbose boot setting in the NVRAM to imply that it's doing some boot process of its own. It'd be great if someone with a bit more knowledge about bootloaders could point me in the right direction.