Can't choose 1st boot device

[ra_sriniketan]

In a Intel original 810 motherboard can't choose the 1st boot device cause its not showing under the "boot" menu.Usually it shows as "Boot device priority" under the "boot" menu.Is there any way to choose the boot device?

[q3_abhi]

Some BIOS do not have the boot priority. They can automatically detect the boot media n then boot.
Some BIOS r different i.e there is a hot key assigned for the Boot menu. (eg:F9).

See the motherboard's manual for more info.