On Sat, Jan 28, 2017 at 2:31 PM, Mick <michaelkintz...@gmail.com> wrote: > > rEFInd is definitely a slick and useful boot manager for multibooting. > On this occasion I did not install it, but decided to remain > minimalist, because I do not want to interfere much with the AppleMac > installation. > > So, I created /boot/EFI/LINUX/ on /dev/sda1, leaving the original > /boot/EFI/APPLE as was and copied in the LINUX/ directory just the > gentoo kernel image, .config and System files. I named the kernel > image 'bootx64-4.4.39-gentoo.efi' to differentiate from other images I > will install over time. > > Then using the efibootmgr I set up bootx64-4.4.39-gentoo.efi as the > default boot kernel and when the MackBook is started it boots straight > into Gentoo, in what it feels like milliseconds. :-) > > When I need to boot into MacOS I have to press the alt key (aka Option > ⌥ key) as I power it on and the Apple firmware boot loader takes over. > What I don't know yet is if a MacOS upgrade will wipe the > /boot/EFI/LINUX/ in /dev/sda1 as it upgrades the APPLE files, but it > is easy to boot with a LiveUSB and copy over the Linux kernel once > more.
Apple doesn't boot from the ESP [1] so it most likely won't touch "/boot/EFI/LINUX/". For example, on my MacBook, the ESP only has what looks like hardware updaters. # diskutil list disk0 /dev/disk0 (internal): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme 500.3 GB disk0 1: EFI EFI 314.6 MB disk0s1 2: Apple_CoreStorage Macintosh HD 499.3 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 # diskutil mount readOnly -mountpoint ESP disk0s1 Volume EFI on disk0s1 mounted # ls -R ESP/EFI APPLE ESP/EFI/APPLE: EXTENSIONS FIRMWARE UPDATERS ESP/EFI/APPLE/EXTENSIONS: Firmware.scap ESP/EFI/APPLE/FIRMWARE: MB91_0154_B09_LOCKED.fd ESP/EFI/APPLE/UPDATERS: MULTIUPDATER USBCH USBCVA ESP/EFI/APPLE/UPDATERS/MULTIUPDATER: HPMUtil.efi Mac-9AE82516C7C6B903.epm MultiUpdater.efi flasher_base.smc Mac-9AE82516C7C6B903-B0_3.72.bin Mac-9AE82516C7C6B903.smc SmcFlasher.efi flasher_update.smc ESP/EFI/APPLE/UPDATERS/USBCH: HPMUtil_v39.efi J93-USBC-NVM-2.72.0-P_B0-S.bin ESP/EFI/APPLE/UPDATERS/USBCVA: HPMUtil.efi fw-p1-USBCVideoAdapter-S.bin # [1] Apple's EFI firmware can read hfsplus and it boots (IIRC since OS X 10.10) from a kernel on the Apple_Boot partition (disk0s3).
