If your board has the u-boot bootloader, when you power up the board, you will see RS232 output like this:
***************************************************
U-Boot 2010.06 (ADI-2010R1-RC2) (Jan 12 2011 - 15:53:34)
CPU: ADSP bf524-0.2 (Detected Rev: 0.2) (spi flash boot)
Board: ADI Advantiv™ Video Evaluation Board
Support: http://ez.analog.com
Clock: VCO: 300 MHz, Core: 300 MHz, System: 100 MHz
RAM: 8 MiB
SF: Detected M25P80 with page size 256, total 1 MiB
In: serial
Out: serial
Err: serial
KGDB: [on serial] ready
Hit any key to stop autoboot: 0
***************************************************
If your board doesn't have the u-boot bootloader, then you will need a Blackfin JTAG adapter (such as ADZS-ICE-1000) in order to upgrade your firmware.
-Matt