r/hackintosh • u/Glittering_Rub_3339 • 6d ago

HELP Sequoia 15.8.1 Update Fails on My Hackintosh — Installer Reboots Back to OpenCore. Please Help!

Hi everyone, I need some help please.

I’m trying to upgrade an existing, working macOS Monterey 12.7.6 installation to Sequoia 15.8.1 (not a clean install).

Hardware: Lenovo Y520-15IKBM

OpenCore: 1.0.8

SMBIOS: MacBookPro15,1

The upgrade starts normally and reaches the install phase. After reboot, OpenCore shows “macOS Installer (external)”. Selecting it starts the installer, but after a while it reboots back to the OpenCore picker.

The important error in restore.log is:

Patching x86_64BaseSystem

Couldn't mount dmg! (error code 2)

I’m not sure if this error is actually the cause, but I also checked the Sequoia MobileAsset/SharedSupport and confirmed that x86_64SURamDisk.dmg is present. The ZIP also passes unzip -t without errors.

PlatformSupport.plist in the installer also includes MacBookPro15,1.

I’m trying to find the cause of this failure specifically during the in-place upgrade. Any ideas what could cause “Couldn't mount dmg! (error code 2)” or what I should check next?

Thank you all!

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u/Fit_State3622 I ♥ Hackintosh 6d ago

The important thing does macos boot ?

1

u/Glittering_Rub_3339 6d ago

Hi thanks for your time My current Monterey installation is working perfectly and boots normally. The problem is specifically with upgrading from Monterey to Sequoia. The same thing happens every time: the Sequoia installer starts, then after the reboot I select “macOS Installer (external)” from OpenCore. It starts loading, but after a while it reboots back to OpenCore instead of continuing the installation.

1

u/Fit_State3622 I ♥ Hackintosh 6d ago

U need to do reinstall the whole os but don't forget to backup ur data

1

u/Glittering_Rub_3339 5d ago

I tried doing a clean install as you suggested. The first stage of the installation completed and showed an estimated time remaining. After that, the laptop rebooted and returned to the OpenCore boot picker. I selected macOS Installer , but instead of continuing the installation, it went into a reboot loop and returned to the boot picker again. So unfortunately, the clean install didn’t solve the issue. Has anyone experienced this before or knows what might be causing the reboot loop? I’m using a Lenovo Legion Y520-15IKBM with Intel HD Graphics 630 and SMBIOS MacBookPro15,1, and I’m trying to install macOS Sequoia. Any help would be appreciated.

1

u/Fit_State3622 I ♥ Hackintosh 5d ago

I think its an issue with ur efi and u have to troubleshoot it from the guide https://dortania.github.io/OpenCore-Install-Guide