Não tenho certeza se você resolveu esse problema, mas acabei de perceber o mesmo problema. Para mim, a chave está em:
┌────────────────────────────────────────────┤ Configuring Secure Boot ├────────────────────────────────────────────┐ │
│ │ Your system has UEFI Secure Boot enabled.
│ │
│ │ UEFI Secure Boot is not compatible with the use of third-party drivers. │ │
│ │ The system will assist you in toggling UEFI Secure Boot. To ensure that this change is being made by you as an │ │ authorized user, and not by an attacker, you must choose a password now and then use the same password after │ │ reboot to confirm the change.
│ │
│ │ If you choose to proceed but do not confirm the password upon reboot, Ubuntu will still be able to boot on your │ │ system but the Secure Boot state will not be changed.
│ │
│ │ If Secure Boot remains enabled on your system, your system may still boot but any hardware that requires │ │ third-party drivers to work correctly may not be usable.
│ │
│ │
│ │
│ └───────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
Depois que o UEFI Secure Boot for desativado, o DKMS criado & carregou o driver muito bem.