Monterey update bricked 2015 iMac
My 2015 iMac was set for auto-updates
Two days ago it performed a Monterey update. No errors but now it won't boot. Goes to the "prohibited" screen
Disk utility shows the drive is intact, but "writeable" is set to "No"
Option to download Sierra OS hangs at the point where it asks for drive volume. No options are given.
In the "compatible device"s list for Monterey the 2015 iMac is not listed.
If so, why did auto-updates allow this to occur?
Can this be fixed?
iMac 27″, macOS 12.6