You are right...
This is a very old MB with Award BIOS version 2.4 release date 02-11-1999.
This bios version does not support booting for USB devices ie pen drive, usb HDD etc.
New version 2.9, released on 2000, is available online, does not say anything about USB booting.
Is there a latest version that supports USB booting ?
MS6119 1.1 BX2 Main board
Award modular V 2.4 021199