Hello @tea-for-one and @oldfred ,
Thank you for your suggestions. Like you suggested, my ACER laptop requires a password to unlock configuration of UEFI Secure Boot.
After setting up the password, I took some liberty to inspect the Boot options. It has “Erase all Secure Boot Setting”, “Restore Secure Boot to Factory Default” and “Select an UEFI file as trusted for executing”. The last one gave me a directory tree:
└── HDD0/
├── EFI/
│ ├── ubuntu/
│ │ ├── grubx64.efi
│ │ ├── shimx64.efi
│ │ └── mmx64.efi
│ └── BOOT/
│ ├── BOOTX64.EFI
│ ├── fbx64.efi
│ └── mx64.efi
└── System Volume Information/
There is another HDD0 directory:
└── HDD0/
├── EFI/
│ ├── Microsoft/
│ │ ├── Boot/
│ │ │ ├── bootmgfw.efi
│ │ │ ├── bootmgr.efi
│ │ │ ├── memtest.efi
│ │ │ └── SecureBootRecovery.efi
│ │ └── Recovery/
│ └── Boot/
└── System Volume Information/
What should I do next?
Best regards,
Hoa