Graphics problem after installing on old iMac 2009

[lordylordy]

I have tried to revive an old imac from 2009 using various distros but consistently get the same problem which is the screen immediately splitting and duplicating into 4 quadrants. The text is unreadable so it's virtually impossible to navigate once it loads. I tried a live edition of Kubuntu and that loads in Safe Graphics mode. I was able to install but when I restarted afterwards the graphics problem happens before the GRUB screen and I don't even get an option to start in Safe Graphics mode etc.


I found a suggested solution online that mentioned loading from a live cd, navigating to the main HDD into etc/x11 and effectively saving a failsafe boot record as a normal boot record and restarting. Then I realised that the post was from 2010 so things have obviously changed quite a bit!

Is there anything I can do? Just to confirm, I can't seem to interrupt the boot operation and change things there because the problem kicks in before that point!

help! Thanks

[Schwarzer Kater]

Could you post the specifications of your iMac? Exact model number, CPU, GPU, etc…

Do you have installed the latest firmware for your iMac? This should be possible in the latest macOS your iMac is able to run (or be done automatically when you fully upgrade the latest macOS for your iMac).