Can’t install/upgrade to macOS Sequoia

[andy_rwalker]

@realmranshuman , @fabiosun if you are still around.
It seems I am struggling exactly the same issue with Sequoia update or install. Installation stuck at the installation screen with about 12 minutes remaining. There is no errors in installations logs. Nothing looks bad. Just installation never past it. Originally I want to upgrade my Sonoma which I managed to upgrade while ago from Big Sur thanks to help from fabiosun but whatever I do I face the same issue. I tried in place update, new installation from USB stick. I gave up sometime ago because nobody could really help or say something. When I saw this post I thought maybe it will work for me as well. So I tried installation approach described in https://github.com/corpnewt/UnPlugged and mentioned by topic starter. Unfortunately it behaves exactly the same. So I created USB stick with two partitions, downloaded Sequoia installation files as described in the guide and copied it to exFAT partition on USB. Booted to recovery partition with Monterey on USB stick and start Unplugged.command. It asked destination where I would like to copy installation files, I selected new, clean partition (for a test to try fresh install of Sequoia), then once coping completed it started ordinary Sequoia installation wizard which I used to select target partition and start install. And then it stuck again when 12 minutes remains. With same events written in installation files. @realmranshuman would you remember what was your experience? Did I do it right or I am missing something.

 

[andy_rwalker]

If anybody interested root cause of my issue seems to be discovered. It seems to be attempt to write to NVRAM crashing my system. My original issue looks like this. If I try to upgrade my MacOS in place installation runs fine and then it suddenly reboots with no kernel panic logs, nothing. Installation logs looks just perfect. It says that all preparation for Installation or Upgrade completed successfully and then bum, reboot. No entry in OC boot picker for Installation/upgrade. If loaded to Sonoma I am asked to start Installation/Upgrade from the very beginning again. If I try installation from USB stick there are same king of installation logs - all good, preparation is complete and then it got frozen. Apparently issue is that when preparation for Upgrade or fresh Install is completed macOS installation daemon has officially closed out its session, unmounted its temporary volumes, and handed control over to the OS to write the NVRAM variables and execute a hardware reboot. In this moment system either crash (if full MacOS) or hand (if this is recovery console like described in Unplugged guide). Easy test I performed is this. When I try to write to NVRAM from my MacOS (Sonoma): sudo nvram MyTestVar=HackintoshSequoia it crash my system immediately. So now at least I know what is wrong.

 

[andy_rwalker]

And finally... My issue is resolved. So to find root cause (MacOS cannot write NVRAM) was the main and most complicated part. As soon as it was identified - everything became much easier. NVRAM issue was due to incorrectly whitelisted MMIO regions. Even though Sonoma was working with them just fine it caused system crash when attempted to write to NVRAM. As soon as right MMIO region was whitelisted standard in place upgrade went just fine. So finally I am on Sequoia version.