All LEDs off?

Hi, my Raspberry with DAC Pro stands in my Music-Room. The LEDS of Status (red green) and Network are very disturbing. I tried to switch them off in config.txt with: #PowerLED dtparam=pwr_led_trigger=none dtparam=pwr_led_activelow=off #StatusLED dtparam=act_led_trigger=none dtparam=act_led_activelow=off #LinkLED dtparam=eth_led0=14 dtparam=eth_led1=14 But by writing I get an Error: [ Error writing /boot/config.txt: Read-only file system ] Is there any Chance to switch of all LEDs?