| `NRV_RUN_FROM_SPI_FLASH` | Do not initialize BRAM with firmware (firmware will be read from SPI flash) |

The default value (25 MHz) corresponds to what is validated by Yosys/NextPNR. If you want you can try overclocking

Note that frequency can only take some predefined values, listed in `RTL/PLL/frequencies.txt`. You can add your own

value there if need be, but then you will need to use `RTL/PLL/gen_pll.sh` to re-generate the board-specific Verilog

for the PLL.