[U-Boot] Reprogramming Flash on GDATech 8540 EVAL board

Hi U-Boot users,

I need to reprogram the Flash device on my GDATech 8540 EVAL board. I installed a non-working u-boot image on to the flash, so I cannot use u-boot anymore to update the bootloader. Please advise me on what is the best way to get u-boot working again.

Thanks, Nikhil Gupta.