My computer is deleting Ubuntu boot entries whenever I try to boot a USB device on it. The USB device overlaps the Ubuntu entry and takes over the first order (FS0), deleting the Ubuntu entry permanently until I recreate it manually.
I bought it with Ubuntu 14.04 LTS installed without Secure Boot and in legacy mode. I'm currently running Ubuntu 16.04 LTS in UEFI, Secure Boot ON and Legacy Support OFF, but I also tried every other setup and it didn't make a difference. Therefore, I assume this is a bug.
Plugs USB device and boots from it
Ubuntu entry remains there
Ubuntu installed, boot entry is created and persists across reboots
plugs in bootable USB device, reboot computer and try to boot it
Ubuntu entry disappears, USB device takes over
then I need to create the entry manually.
IMPORTANT NOTE: this only affects Ubuntu entries. Fedora Linux, Arch Linux or any other keep their UEFI entries intact in the computer BIOS. Ubuntu has modified its placement and naming of boot files. Some will say that it's Ubuntu's fault, but since Ubuntu is supported by Dell, there should be some changes you can apply to the BIOS firmware in order to avoid this problem.