This quite a long road but will try to shorten the path
For some reasons, I decided to downgrade back to macOS Catalina from Big Sur
Since I had no TimeMachine backup and could not do a backup either (available free drives 😅)
So I free enough space from my SSD created another APFS volume
I downloaded Catalina 10.15.7 (This did not include the latest supplemental update 2), created a bootable USB, and did the installation.
Everything when well, I then Copy everything from my User folder to Catalina (yes .composer, etc included), The Applications as well as the respective files from /Library, StartupItems, LaunchAgents, LaunchDaemons, PrivillegeHelperTools, etc, also my brew installation folder.
Once all was done I deleted Big Sur and started using Catalina no issue except for Safari (was insanely using RAM) but no other issues
Then I got a software update notification but did not install it directly instead I downloaded the installer from the support page (This time 10.15.7 sup update 2) did the install, no issue.
A few days later go another notification for safari did the update (V14.0), then another update 2 days ago I think Safari 14.1 & a Catalina update 10.15.7 (about 1.35GB) it after installing this update that it all started.
The first thing I notice is that the update might have introduced some change to facilitate the upgrade to macOS 11 (Guessing here but seam that based on what follows).
SIP was disabled when I did the update, so once it was done I booted into recovery mode and the welcome was looking like macOS 11, I mount the drive for some reasons and then disable SIP after a reboot my mac would not boot, it will start then I get the Prohibited sign
Since I had no backup did not want to reinstall so in recovery mode I tried to fix the drive and got a warning: Container has been mounted by APFS Version 1677.81.1, which is newer than 1412.121.2, and other about overallocation
I managed to fix the overallocation my run fsck_apfs with -o option but not Container has been...
Still could not boot (Normal Login, Safe Mode, Single User) always Prohibited sign
I started making some change, moved all StartupItems, LaunchAgents, LaunchDaemons, PrivillegeHelperTools from the library folder in case one was the root of the problem same thing
Then from Terminal (Recovery Mode), I resize the container (This did the trick) and after rebooting I still could not log in instead showing the Prohibited sign now the mac just froze at about 70% of the loading bar after entering my password.
So I did an NVRAM/PRAM reset and finally booting, Then I tried to disable SIP again since an NVRAM reenabled it, the same thing after entering my password it freezes at about 70-80%.
Today after installing Lulu (not sure if that was the trigger) but upon rebooting the same thing again Prohibited sign.
Repeated the step I took to solve it the first time but no success this time, then I got it working using diskutil apfs updatePreboot /dev/disk2s8
But still can pass the login screen after inputting my password with SIP disabled
For some reasons, I decided to downgrade back to macOS Catalina from Big Sur
Since I had no TimeMachine backup and could not do a backup either (available free drives 😅)
So I free enough space from my SSD created another APFS volume
I downloaded Catalina 10.15.7 (This did not include the latest supplemental update 2), created a bootable USB, and did the installation.
Everything when well, I then Copy everything from my User folder to Catalina (yes .composer, etc included), The Applications as well as the respective files from /Library, StartupItems, LaunchAgents, LaunchDaemons, PrivillegeHelperTools, etc, also my brew installation folder.
Once all was done I deleted Big Sur and started using Catalina no issue except for Safari (was insanely using RAM) but no other issues
Then I got a software update notification but did not install it directly instead I downloaded the installer from the support page (This time 10.15.7 sup update 2) did the install, no issue.
A few days later go another notification for safari did the update (V14.0), then another update 2 days ago I think Safari 14.1 & a Catalina update 10.15.7 (about 1.35GB) it after installing this update that it all started.
The first thing I notice is that the update might have introduced some change to facilitate the upgrade to macOS 11 (Guessing here but seam that based on what follows).
SIP was disabled when I did the update, so once it was done I booted into recovery mode and the welcome was looking like macOS 11, I mount the drive for some reasons and then disable SIP after a reboot my mac would not boot, it will start then I get the Prohibited sign
Since I had no backup did not want to reinstall so in recovery mode I tried to fix the drive and got a warning: Container has been mounted by APFS Version 1677.81.1, which is newer than 1412.121.2, and other about overallocation
I managed to fix the overallocation my run fsck_apfs with -o option but not Container has been...
Still could not boot (Normal Login, Safe Mode, Single User) always Prohibited sign
I started making some change, moved all StartupItems, LaunchAgents, LaunchDaemons, PrivillegeHelperTools from the library folder in case one was the root of the problem same thing
Then from Terminal (Recovery Mode), I resize the container (This did the trick) and after rebooting I still could not log in instead showing the Prohibited sign now the mac just froze at about 70% of the loading bar after entering my password.
So I did an NVRAM/PRAM reset and finally booting, Then I tried to disable SIP again since an NVRAM reenabled it, the same thing after entering my password it freezes at about 70-80%.
Today after installing Lulu (not sure if that was the trigger) but upon rebooting the same thing again Prohibited sign.
Repeated the step I took to solve it the first time but no success this time, then I got it working using diskutil apfs updatePreboot /dev/disk2s8
But still can pass the login screen after inputting my password with SIP disabled