I am trying to install the latest version (5.0) on my late 2009 27“ iMac. It has a 2.66 i5 processor and an ATI Radeon HD 4850 GPU.
To get my USB stick to boot I have to replace "no splash" with "nomodeset" and the install goes fine. However, when I try to boot the OS after installation I get a black screen and Grub doesn't appear at all so there is no way for me to make that same change to the boot options.
Any help would be greatly appreciated.