Hi i got an imac 27" 2020 in with failed update (from catalina to Monterey)
turn on yellow screen
I started in Transfer Mode and made a backup from the data
then started DFU Mode and made a reset, after that i started with alt and "R" and got Catalina installed, normaly running seems all ok
I started the Update for Monterey and got the same result like my client, a yellow screen ( after the apple and about 2:30h installing)
now, starting with "alt" and "R" it is not possible catalina to install, only Monterey, so that means for me the bios is new flashed also
I attach a file with the yellow screen, only cursor is to see
I just now have no idea what this can be
turn on yellow screen
I started in Transfer Mode and made a backup from the data
then started DFU Mode and made a reset, after that i started with alt and "R" and got Catalina installed, normaly running seems all ok
I started the Update for Monterey and got the same result like my client, a yellow screen ( after the apple and about 2:30h installing)
now, starting with "alt" and "R" it is not possible catalina to install, only Monterey, so that means for me the bios is new flashed also
I attach a file with the yellow screen, only cursor is to see
I just now have no idea what this can be