@User @User , its good to use only mrpj_io[37:12] for user_project , pls confirm .

More or less. Only mrpj_io[5:0] are truly necessary to stay away from unless absolutely needed, and mprj_io[37:36] needs to be added to that list for the caravel updates for MPW-two, because those two pins will allow full QSPI access to the flash SPI for the management SoC. [11:6] might be connected to additional pins on the development board and might end requiring cuts or jumpers depending on how the board ends up being designed. So [35:12] will be the easist to use, no issues, but you can make use of the other pins if you pay attention to how the development board is set up and know what else those pins might be connected to on the board.