this is really a pity - as far as I know, you cannot reprogramm the board without the Infineon specific CAN adapter and software in case the boot loader is erased.
But you could try, if the Bootloader is still present: Please start the TRINAMIC TMCL-IDE and try finding the board (set the port and baudrate). If possible, you can install the firmware again.
If you are not successfull, please contact your distributor - he can send in the board for reprogramming or exchange it. Do you want to use the 8 bit processor? If you want to use a more powerfull CPU, we could exchange it with the latest version with 32 bit CPU and new firmware and source code - please refer to this posting, then we will exchange it if you like.