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Installing macOS Sequoia 15.8.2 — Dell G3 3579

This guide is for Sequoia only. For Sonoma, use Sonoma installation.

The EFI in this repository is tested with macOS Sequoia 15.8.2 (24H232) on this laptop. There are two ways to prepare the installer; pick one before you touch the USB.

Online Recovery Full offline installer
Initial download small recovery image many GB
Internet during installation required only for later setup and updates
Version installed whatever Apple currently serves (usually the newest 15.x) the exact build of the installer you keep
Repeat installs download the recovery image again reuse the same installer
Good for first install, little storage reproducing a build, avoiding repeated downloads

The tested installation on this laptop used the full installer. Recovery is supported and works the same way, but it will not necessarily give you 15.8.2 — it serves whatever Sequoia build Apple currently offers for the board ID.

Before you start

Option A — Online Recovery

Recovery boots a small image fetched from Apple and downloads the rest of macOS while it installs. It therefore needs working internet inside the installer — check that Wi-Fi or Ethernet works there before committing to this route. If neither does, use the full installer instead.

  1. Get macrecovery.py from Utilities/macrecovery/ in OpenCorePkg and run it for the current release:
python3 macrecovery.py -b Mac-937A206F2EE63C01 -m 00000000000000000 download

On Windows use py instead of python3. That board ID is Dortania's “latest version” entry; confirmation and the full list are in the installer guide.

  1. The script writes BaseSystem.dmg with its .chunklist (or RecoveryImage.*). That is the boot image only — much smaller than a full macOS installer.

  2. Format the USB as MS-DOS (FAT32) with a GUID partition map. Create a folder named com.apple.recovery.boot at the root and copy both downloaded files into it.

  3. Copy the EFI folder from this repository to the USB root as well, so the root contains EFI/ and com.apple.recovery.boot/.

  4. Boot from the USB (F12 → UEFI USB), select the recovery entry, and install.

The Sequoia build you end up with is whatever Apple currently serves; it may be newer than 15.8.2. If you specifically need 15.8.2, use Option B with a full installer of that build.

Option B — Full offline installer

A full installer is a complete copy of macOS that can be written to a USB stick and kept for later. It is the only way to reproduce an exact build.

  1. Obtain the installer from Apple: download macOS. On a compatible Mac, softwareupdate --fetch-full-installer is another route, but it does not offer every version on every host — check what it lists before relying on it.

  2. Depending on the source you get either Install macOS Sequoia.app directly or an InstallAssistant.pkg that installs that app into /Applications when opened. Both end up as the same application.

  3. Write it to the USB with Apple's tool (create a bootable installer):

sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia \
     --volume /Volumes/MyUSB

Use a 16 GB or larger stick formatted Mac OS Extended (Journaled) with a GUID partition map. createinstallmedia refuses APFS targets and erases the volume it is given.

  1. Mount the USB's EFI partition and copy this repository's EFI folder into it as EFI/.

  2. Boot from the USB and install.

I keep a full installer on a separate drive. OpenCore experiments, macOS updates and failed boots can mean reinstalling more than once, and downloading many gigabytes again each time is wasteful — a local copy makes a reinstall much quicker. It is optional, not a requirement.

"Offline" refers to the installer only: signing in, iCloud and updates still use the network after installation.

Booting the installer

  • Boot from the USB (F12 → UEFI USB).
  • In OpenCore, choose the macOS installer entry.
  • If the screen goes dark during boot, press Fn+Insert to toggle the display — see display backlight.
  • If the installer hangs at still waiting for root device, the USB stick is on a port that UTBMap.kext prunes. Disable UTBMap in Kernel → Add for the installation and re-enable it afterwards; Bluetooth needs it to enumerate. See fixes.
  • If you install alongside another OS, select the correct target volume in Disk Utility and back up first. Do not erase a volume you need.

Installing

The installer reboots several times. Boot from the USB each time and select the “macOS Installer” or target-volume entry until setup completes.

Making it boot without the USB

Copy the personalized EFI/ to the internal disk's EFI partition. Keep a backup of the previous EFI, and on a multiboot disk preserve the existing Microsoft/ and vendor folders.

If it fails to boot

Boot the USB OpenCore stick or restore the previous EFI. See known issues.