8. Using the ECO Compilation Flow
ECOs typically occur during the design verification stage. For example, during verification you may determine that the design requires a small change, such as a netlist connection change, correcting a LUT logic error, or placing a node in a new location. Implementing an ECO change, rather than changing RTL and fully recompiling the design, requires significantly less time, and changes only the affected logic.
You specify the ECO commands in a Tcl script using the ::quartus::eco package.