Hey... I have just tried to boot legacy, however I am unable to reach clover when doing so.
Even though the USB drive is selected as the boot device, the notebook takes me to a bios utility after the dell initial screen. I created a new MBR flash drive, with two partitions as instructed in the guide.
Booting the same media via UEFI results in the same old osxaptiofixdrv error.
EDIT: After 3 more tries in UEFI (without changing any settings on config, files on the USB drive or anything else), I was able to boot into the installer, but there was absolutely no backlight on the display. With the help of a flashlight, I was able to go through the installation without problems.
After installation, however, I am stuck on the 2 lines of death again. I didn't change anything on BIOS or on the USB drive and the error is happening again.
Now what? lol