I just bought a new laptop which comes with Windows 10 on a 256gb SSD. There is no other disk storage.
The Windows 10 install has to stay because it's for my wife to use. I then used a Kubuntu (18.04) USB installer to install Kubuntu. During install, it asked if I wanted to install proprietary graphics drivers, and that doing so I would have to disable Secure Boot. I didn't really think about that at the time and just checked the boxes and set up the password (big mistake). I then assigned Kubuntu roughly half the existing drive (so Windows was shrunk to ~140gb with ~110 for Kubuntu).
Now, when the computer boots, it boots straight to Windows 10 (instead of giving us the option of either). In order to access the Kubuntu partition, I have to boot Windows 10, then access the Secure Boot menu from within Windows and restart treating the Kubuntu partition like booting from an external device. To fix this, I went to re-install Kubuntu over the existing Legacy installation, but the Kubuntu installer doesn't recognize the Legacy installation (probably because the bootable USB is being booted from UEFI). Is there any way to fix this without reformatting the entire drive (including Windows 10)?