remote update, boot soft at another addr from flash

Hi, here's my setup:

I would use the remote update ip to make a firmware update of my product. The customer just have to launch a firmware update, the software take the decision to place the rpd file that contains fpga+soft at the addr A of B. But I dont know which one of these addr the soft will choice.

If i made a fpga with a reset software addr at 0x00200000 and that I place this fpga at the addr A, I want the NIOS to boot at the addr A+0x00200000. If the same fpga is place at the addr B, i want the NIOS to boot at the addr B+0x00200000.

I use a 5CEFA4F23C8 fpga, quartus prime lite edition with a license for nios2, a N25Q256 flash memory.

Thx for your reply.