Press and . Release the button.
Keep holding both buttons. Release the while continuing to hold the Power button . Tap the Stop button 5 times , then release the Power button .
If the green light stays solid, your Canon MG2540s is successfully in Service Mode. Windows may detect it as a new device. You can now use official service tools (like Canon Service Tool V3400 or V4904) on your computer to clear the waste ink counter. Turn the printer off and on again to exit Service Mode.