Am I understanding Apple Macbook's EFI Boot Process?

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Am I understanding Apple Macbook's EFI Boot Process?

Postby nsuchy » 2018-05-03 15:36


I have made the switch to Debian and so far so good but I have a few questions about the Apple Macbook's EFI Boot Process.

The firmware checks the SSD for an EFI Partition which handles anything boot related. You can access this in Debian at /boot/efi. My EFI partition has a file named BOOTLOG and then another folder named EFI, inside are two folders, one named Apple and another named Debian. If my macOS USB is plugged in macOS gets loaded from it - I assume the Apple folder contains the needed information, otherwise the screen goes black for about 10 seconds then loads Debian.

As previously stated have a USB Key with macOS Sierra installed - this key is used exclusively to update the Macbook's system firmware since Debian has no way of doing so.

Now I would like to control the boot order. Right now Debian takes quite some time before the system gives up trying to load macOS and falls to Debian. Where is boot order controlled and how can I adjust it? I'd prefer for Debian to boot first and to use the option key if I want to load my macOS USB for firmware updates.

Thank you for any help that you can provide,
Nathaniel :)

Code: Select all
root@Nathaniels-MacBook-Pro:/home/nathanielrsuchy# efibootmgr -v
BootCurrent: 0002
Timeout: 5 seconds
BootOrder: 0002,0080
Boot0002* debian   HD(1,GPT,b0d99636-44ef-481a-8592-df1dc4249f2b,0x800,0x100000)/File(\EFI\debian\grubx64.efi)
Boot0080* Mac OS X   PciRoot(0x0)/Pci(0x14,0x0)/USB(0,0)/HD(2,GPT,8e938f80-e2f5-4e2c-9159-7df927c8e373,0x64028,0x39d8490)

So far I've found that efibootmgr has made the changes I was looking for. That said where are these boot settings being stored? Anything else I should know?
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Joined: 2018-05-03 15:28

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