So to double check, the jumper has been inserted as listed in the manual thus in essence using BIOS_A or the primary BIOS.
Are you able to gain access to the BIOS itself and if so, could you reset to factory defaults and then power cycle?
If not then perform a CLR_CMOS by jumping the pins as listed in the manual:
"CLRCMOS1 allows you to clear the data in CMOS. To clear and reset the system
parameters to default setup, please turn off the computer and unplug the power
cord from the power supply. After waiting for 15 seconds, use a jumper cap to
short pin2 and pin3 on CLRCMOS1 for 5 seconds. However, please do not clear
the CMOS right after you update the BIOS. If you need to clear the CMOS when
you just finish updating the BIOS...