Xenon in weird state and cannot get back to DFU mode

Here is my code.

SYSTEM_MODE(MANUAL);
SYSTEM_THREAD(ENABLED);

void setup() {
  System.sleep(D2, RISING, 10000);
}

void loop() {

}

After flashing the device and letting it go to sleep I realized the 3rd parameter is seconds not milliseconds. No big deal, I try to hold reset and mode at the same time, then release reset to get to DFU mode. But instead, the device starts blinking red as soon as I let up on reset and then goes to flashing red ten times.

Also hitting reset by itself should cause the Xenon to fire up and then go back to sleep but it causes the red flashing panic state. Only pulling power and reapplying power does it fire up correctly and then go to sleep. However, I cannot get it into DFU mode to update the firmware.

Any ideas what is going on, or how to proceed from here?

thanks

Ok, figured it out. Key is to unplug the device, then hold both reset and mode together and then apply power. I was then able to enter DFU mode.