Summary: I can boot my Dell Precision 7510 laptop into Ubuntu using a boot USB, but after installing and removing the USB, the laptop fails to boot into the installed Ubuntu OS.
I've installed Ubuntu on this laptop before and never had any issues, after installing the laptop would boot into the Ubuntu OS by default. However, when trying to install Ubuntu 21.04 recently that isn't the case. After installing Ubuntu 21.04 via USB and rebooting without the USB, the laptop boots past the dell logo screen where you can enter the BIOS menu, but afterward just freezes on a black screen. When entering the BIOS menu I can see 'ubuntu' recognized as the first option in the boot order under the UEFI options, and even when I select it manually it still ends up going to a black screen and freezing.
I don't know much about the BIOS boot options to be honest, but I've tried every combination of SecureBoot on/off, UEFI boot on/off and legacy boot options on/off that I can with no luck. I've also tried running the Ubuntu 21.04 installation options in a few different ways (eg, completely erase disk and install, reformat to ZFS and install, etc) and even tried making a new bootable USB just in case that was the issue, but everything ends up with the same result.
While Googling the problem I came across some suggestions that grub might be the problem, with a suggested solution of booting from the USB, installing the Boot Repair utility, running "Recommended Repairs" and seeing if that resolves the issue. I tried this, but found an interesting catch 22 in that the Boot Repair utility can't do anything when the machine is in legacy boot mode and requests trying again in UEFI mode, yet I can ONLY boot from the USB in legacy boot mode (UEFI doesn't seem to see the USB as a boot option).
Just to be clear about my goals, I'm not dual-booting and there's nothing important on the laptop so completely formatting the harddrive or doing an installation that erases everything on the disk to set it right is not an issue at all.
I'm out of my wheelhouse when it comes to troubleshooting hardware issues, and I'm not super familiar with disk partitioning/Grub/BIOS/UEFI stuff in general so its possible that I'm describing some of this incorrectly but I'm doing my best. I've reached the end of what I'm able to try on my own and looking for some advice on what to try next because I like this laptop and its currently unusable.
