Chosen Solution
iMac bricked! Neither Recovery Mode nor Internet recovery worked. Couldn’t install High Sierra via bootable Drive. Tried a Catalina patch and it finally recovered. Now having too many issues with Catalina. Need to test downgrading. Recovery Mode and Internet Recovery still does not work upon start up. Safe mode returns a Circle Cross out. I have backed up the Mac via Time Machine + External with Catalina. I now can’t figure out how to erase my HD, install Mojave from my bootable USB, without the system able to go in recovery mode. Am I forced to use command line sequence to accomplish this? Any help appreciated.
Sadly, you need to work from an external bootable drive to completely wipe the drive and then rebuild. With the current version of APFS you can’t back off! Apple is still altering the drives structure under APFS (still a work in progress!) Now the fun part! Apple messed up the certificates in the older macOS releases Sierra, High Sierra & Mojave! You need to get the fixed files: How to upgrade to macOS SierraHow to upgrade to macOS High SierraHow to upgrade to macOS Mojave Here’s more on the certificate issue If you’ve got an old macOS install image, it will probably stop working today
