Thanks for the response Jcolvin and Zygot.
@zygot: The motivation for wanting to do this change is: I want my arty 35t eval board to interface with a custom IC that has a 1.2V IO interface. By default, I see that the supply voltage for all the IO banks on the Digilent Arty 35t FPGA eval board are connected to 3.3V. I am looking for a way to operate the IO pins of the digilent arty 35t eval board at 1.2V instead of 3.3V.
Based on your response, it clearly looks like the best option for me would be to use the Mimias A7 eval board. The supply voltage to IO banks 15 and 16 are adjustable on the Mimias A7 board.