Check the manual to see what the LED color means. If you are 100% you are not having any of those issues, your only option is to debrick the device.
There are two guides, both mentioned on the guides:
Added:
Since it seems two devices die for you, is there anything you are doing in regards to power by any chance? Or do you experience power outages due to storms where you are? Usually that is when the device dies. Since there is not a power button, lots of users just unplug it, which is a big no-no! To shut down properly, it can be done via the dashboard and/or the command line.
