I have a 13" 2018 MacBook Pro. My System Integrity Protection is off, and T2 security is set to
None. After an update to MacOS Catalina 10.15.3, my mac would stay at the bootup screen with an apple logo. I salvaged all my data in recovery mode and tried to reinstall MacOS from there. I ended up getting
A software update is required to use this startup disk error in recovery. I then completely wiped the internal SSD, and using another mac and disk drill made a bootable USB with MacOS 10.15.3. I booted that and got the same
A software update is required to use this startup disk error in recovery. I tried to reset the mac to its original OS after that with
R, but after loading with a rotating earth for a few minutes I get an exclamation mark sign over that earth with the following below it:
Regarding the inability to boot the MacOS USB stick, I've read that the newer macs can only boot from APFS drives. However, I do not know how to do that. After using disk drill to flash MacOS to a USB, I tried using a disk utility option
Convert to APFS..., but that threw an error.
I have no idea what to do anymore, and would rather not go to an apple store to fix this. Is it even possible for a genius bar person to fix the software? How could I fix this myself? I do have access to a few decently sized USB drives and a tri boot Windows/Linux/MacOS computer, but no professional tools.
I would like to add I have not been able to install linux either onto my Mac, and not even rEFInd.