I have a Dell XPS 15 9550, with Nvidia graphics card. My Windows 10 runs in UEFI mode, and I want to dual boot it with Ubuntu. When I try to install Ubuntu 20.04.2 from USB prepared with Rufus, MBR(UEFI or Legacy) selected, it would always install in legacy mode (It would directly boot into Linux when I change the firmware settings to Legacy, and directly into Windows 10 when UEFI is selected). If I prepare the USB with Ubuntu using Rufus to boot in UEFI only (GPT, FAT32) it does not boot at all. Grub screen appears, and when I select Ubuntu I get a black screen (but the PC stays on, it does not keep rebooting or cycling). I have also tried different distributions (like Mint), but the same thing happens. I tried the same USB with a different PC and it boots normally with any distribution. I tried different ports on my PC, and a different USB but it still won't work.
I have tried disabling secure boot, fast startup, hibernation, disabling legacy option roms, disabling attempt legacy boot. I tried increasing brightness after GRUB, changing GRUB boot options (adding nomodeset, changing to no splash, nouveau.modeset=0).
I have also tried to install Ubuntu in legacy mode, and then switch it to UEFI using boot repair, and I do see the "Separate /boot/efi partition" line (there is indeed and efi partition present in my PC), but the boot-repair tool requires disabling legacy mode in firmware settings first. I don't know how to proceed after this since my PC boots directly into Windows 10 if I disable legacy, so I can't access Linux or boot-repair anymore.
I have even tried disabling NVIDIA, since I also have the integrated graphics card, but it did not do a thing (maybe it only applied to my Windows session since I did it there).
I have been trying to set this up for the last couple of days and I have tried all of the suggestions that I found on other threads/forums. If anyone has any idea please help :)
Update: I have managed to successfully boot and install Fedora Linux, but Ubuntu and Mint get stuck at black screen after GRUB