USB drive not detected in BIOS

[14v]

After I installed Ubuntu Mate via Multibootusb on the flash drive it disappeared from the BIOS boot menu. Motherboard is Gigabyte 965p s3 f15. boot flag is set and I can boot from this flash on Acer notebook. Other flash drive, not bootable, with some files is shown in BIOS menu.

What can I check else to find an issue?

[conceptrat]

Perhaps you have UEFI (not Legacy) and "Secure Boot" enabled in the BIOS of this motherboard?

When using UEFI and Secure Boot you won't be allowed to booting from USB. So either switch to "Legacy Boot" instead of UEFI or turn off "Secure Boot".

If you're using UEFI and have switched off "Secure Boot" and it's still not working then the other possibility is that the USB boot disk you have created is formatted using NTFS instead of FAT32. UEFI systems don't typically support booting NTFS.

Someone else may be able to eleaborate on this further.

[14v]

This is old motherboard without UEFI. Still actual for other distros. Need to dd iso or "write image to disk" then usb drive detected.