If the firmware update has failed; Be it, the percentage circle is stuck on 0%, or the 2nd or 4th green LEDs on the light are illuminated, then the firmware update may have stalled for some reason and is waiting on the update to conclude before you can use the light. In order to get the light working again, you should shut down the app and re-open, or you can also uninstall and reinstall the app to stsrt fro mfresh and the light should recommence the firmware update.