From the first iso, obtained on step 3, copy BaseSystem.chunklist and BaseSystem.dmg on the thumb drive (actually, the latter might not be necessary - but it worked for me at this step and I stopped experimenting). Before you begin, you’ll need to download the macOS version you’d like to use directly from Apple. For the sake of clarity, we’ll simply refer to any external drive as a USB drive. Mount the thumb drive (you might need to apt-get install hfsprogs to mount an HFS filesystem). Whether it’s an external hard drive or a USB ‘thumb’ drive, both are considered bootable drives. IMPORTANT NOTE: The name can be anything but be sure to use Mac OS Extended (Journaled) format & GUID.
#How to use a bootable usb imac how to#
In my case (High Sierra 10.13.6), 4Gb stick was sufficient, even though createinstallmedia requires 8Gb. How to create a macOS 12 Monterey USB Boot Disk. iso as well ( dmg2iso -i BaseSystem.dmg -o BaseSystem.iso)Ĭopy it to a thumb drive: dd if=BaseSystem.iso of=/dev/sdX BS=1M. iso įind BaseSystem.dmg in the mounted image. You can do it from GUI (right click, "Open with disk image mounter") or something like mount -o loop. Now type the command select disk followed by the assigned number for the flash drive select disk 4, and press Enter again. Using the macOS Big Sur USB installer Creating the USB installer drive is easy, but actually using it can be challenging for users running Macs with Apple T2 Security chips. Enter the list disk command to each drive connected to your PC and press Enter.
So, you'll need to find an alternative source.Ĭonvert. Type the command diskpart and press Enter. This question on apple support has all the links, but they are only accessible from OS X (if you had access to a live OS X at this point - you probably would've just used createinstallmedia already, right?). Unlike El Capitan, High Sierra only needs BaseSystem.dmg, which also has enough free space to boot - so, the process overall can be simplified a bit. So, leaving it here in case somebody else will need to. I recently had to make a High Sierra 10.13.6 bootable USB drive, and the process turned out a bit more involved that just dd-ing the dmg2img-generated ISO to a thumb drive.