Not able to connect debugger to AduCM331.

I work with Bootloaders, While testing with ADuCm330 EVB, I mistakenly overwritten the memory area 0x00 – 0x10, It gave me a hard fault and I have not been able to connect my debugger to the EVB since then. The current status of the EVB is that it does not have a valid bootloader flashed on it and page zero checksum bytes (Address 0x7FC) are 0x16400000. I am unable to understand why the debugger cannot connect to the EVB. Can you help us in this regard? I use segger J-linki minikit debugger and keil, IAR IDE and JFlash tools but none of them works.