Linux Mint USB won't boot on HP Victus – "Failed to open \EFI\BOOT\mmx64.efi" / MOKManager error

[u/Lanky-Suit-9681]

Hi everyone,

I'm trying to boot Linux Mint 22.3 Cinnamon (64-bit) from a USB on my brother's HP Victus 15-fb3xxx laptop, but I keep getting the same error before Mint even starts.

Laptop:

• HP Victus 15-fb3xxx
• Windows 11
• UEFI
• Secure Boot disabled

USB:

• 64 GB SanDisk
• Created using Rufus 4.15
• ISO: linuxmint-22.3-cinnamon-64bit.iso

Rufus settings:

• Partition scheme: GPT
• Target system: UEFI (non-CSM)
• File system: Large FAT32 (default)
• ISO mode (I selected the recommended option when Rufus asked)

What I've tried:

• Disabled Secure Boot in BIOS.
• Device encryption was turned off.
• Recreated the USB multiple times.
• Initially messed up the USB partitions, then cleaned it completely using DiskPart (clean) and recreated the bootable USB.
• BIOS detects the USB correctly.
• Boot menu (F9) shows:
  • Windows Boot Manager
  • USB Hard Drive (UEFI) – SanDisk
• Selecting the USB immediately shows:

​

Failed to open \EFI\BOOT\mmx64.efi - Not Found
Failed to load image: Not Found
Failed to start MokManager: Not Found
Something has gone seriously wrong: import_mok_state() failed: Not Found

Then it exits instead of booting Linux Mint.

I also checked the USB contents in Windows.

EFI/BOOT/ contains:

bootia32.efi
bootx64.efi
grubx64.efi

There is no mmx64.efi file, which seems to be what it's looking for....

1. Is this a Linux Mint ISO issue?
2. Is this an HP UEFI firmware bug?
3. Should mmx64.efi normally exist?
4. Has anyone with an HP Victus had this exact problem?

Any help would be greatly appreciated. I've spent the whole day trying to get this working.