So I'm new to MacOS, I have a M1 MacBook and I have a friend that needs to restore an old MacBook but he's on macOS Sierra. I've tried to restore from his MacBook directly but it always fails.
I've verified his Mac can upgrade to macOS High Sierra but I can't figure out how to make a bootable drive for it. I can't download High Sierra from the App Store, like most tutorials say, because the App Store says it not compatible with my Mac.
So I've downloaded the dmg file from Apple and that's where I'm stuck. I can't figure out how to make a bootable drive from this dmg file.
Any help is appreciated!
How to: Create bootable USB from a .dmg f… - Apple Community
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How do I make USB bootable from an ISO file on a Mac?
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What format does a USB need to be bootable for Mac?
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Use TransMac, which has a 15-day trial period and works flawlessly.
In the left pane, right click the USB Drive and select Format Disk for Mac
In the left pane, right click the USB Drive and select Restore with Disk Image
Point to your .dmg (or choose All Files to select an .iso) file and click Open.
It will take a few minutes depending on size of .dmg and speed of USB drive, but once done you can pop it into your mac, hold down the option key when turning on the mac and choose the USB drive.
TransMac worked for me, but first you need to partition your USB drive with GPT. It will not work if partitioned as MBR. diskpart on Windows can do this:
diskpart
DISKPART> list disk
(Find the disk number)
DISKPART> select disk 2
Disk 2 is now the selected disk.
DISKPART> clean
DiskPart succeeded in cleaning the disk.
DISKPART> convert gpt
DiskPart successfully converted the selected disk to GPT format.
DISKPART> create partition primary
Here's what you need to do, you have two options:
Use Internet Recovery to install Yosemite, like you were doing earlier, and then either upgrade to macOS Sierra via the App Store or just download the macOS Sierra upgrade to create a macOS Sierra USB Installer from.
To create a macOS Sierra USB Installer you need a working Mac so you can download macOS Sierra from the App Store and with a blank USB stick run this command via Terminal. Make sure you first reformat the USB stick using Disk Utility to Mac OS X Extended (Journaled). Also rename the USB stick to: Untitled
Use the following command:
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ Sierra.app --nointeractionThen perform a clean install using the macOS Sierra USB Installer.
If you have "Install macOS Sierra.dmg", Install it and you will get the app "Install mac OS Sierra.app" installed on your applications folder.
So to be clear, installing "Install macOS Sierra.dmg" will not install Sierra OS on the current computer but only puts the "Install macOS Sierra" app inside the applications folder.
This way you get the app. And you create the bootable USB by running the command given by Maximus.
Hope this help!
There's a ready script that automates this whole process. Manually it's as mentioned in MacWorld, but using the Linux tools:
InstallESD.dmg is an image of a GPT disk with HFS+ partition which contains installer files, but is not bootable itself.
Working as a root, convert InstallESD.dmg into raw image format and mount it using kpartx:
dmg2img InstallESD.dmg InstallESD.img
kpartx -a InstallESD.img
mount /dev/mapper/loop0p2 /mnt/installesd
InstallESD.dmg contains another disk image, BaseSystem.dmg, which is a bootable installer disk. But writing it directly to the USB drive does not work, because that would create a partition with almost no free space and still lacking some important files.
Extract base system image BaseSystem.dmg, convert into raw and mount too:
dmg2img /mnt/installesd/BaseSystem.dmg BaseSystem.img
kpartx -a BaseSystem.img
mount /dev/mapper/loop1p1 /mnt/basesystem
Format the USB flash drive as HFS+:
sgdisk -o /dev/sdb
sgdisk -n 1:0:0 -t 1:AF00 -c 1:"disk image" -A 1:set:2 /dev/sdb
mkfs.hfsplus -v "OS X Base System" /dev/sdb1
mount /dev/sdb1 /mnt/usbstick
Copy missing installer files (beware of ending /):
rsync -aAEHW --info=progress2 /mnt/basesystem/ /mnt/usbstick/
rm -f /mnt/usbstick/System/Installation/Packages
rsync -aAEHW -P /mnt/installesd/Packages /mnt/usbstick/System/Installation/
rsync -aAEHW -P /mnt/installesd/BaseSystem.dmg /mnt/usbstick/
rsync -aAEHW -P /mnt/installesd/BaseSystem.chunklist /mnt/usbstick/
sync
It is possible to copy with other tools (tar, cpio), just supply parameters preserving the most of file metadata. rsync supports also -X parameter, supposed to copy HFS+ extended attributes, but in practice it fails with the error "Operation not supported".
If you can't start up from OS X Recovery (Option-R), try holding down (Option-Command-R) to start up from OS X Internet Recovery.
Your mac(mid-2015) should initiate recovery over the Internet.
Read more at https://support.apple.com/en-us/HT201314