The linker script specifies that .data section starts where 192k RAM region starts - in other words, addresses of all variables, etc, are in the RAM memory rang

The linker script specifies that .data section starts where 192k RAM region starts - in other words, addresses of all variables, etc, are in the RAM memory range. But the firmware image (that resides on flash), which has .text and .data concatenated, has that .data section in Flash region, obviously. So we have .data section residing in Flash region, but all its addresses in the RAM memory range. That's why it is necessary to copy it over manually. Hope this is clear... Let me know if not!