what operating system are you running?
Try
cat /etc/issue
if it is Debian 7 (wheezy), then get the file from here.
Otherwise, if it says Debian 9 (stretch), get the file from here.
The way to disable the LEDs without changing the dtb is:
echo none > /sys/class/leds/beaglebone\:green\:usr0/trigger
echo none > /sys/class/leds/beaglebone\:green\:usr1/trigger
echo none > /sys/class/leds/beaglebone\:green\:usr2/trigger