If your firmware is not able to download, then it could be because it is not the correct version for your Cobblestone. There are two versions of the Cobblestone hardware unit, the old version and the newer version. To determine which firmware version to download, you will need to first check the version of your Cobblestone.
Note: If you run into this issue while updating your firmware: "Firmware checksum failed on upgrade, system will reboot." this is because you have an older version of the Cobblestone that does not support the newer firmware.
Please check if you have the newer or older version by following the steps below:
1. Select Cobblestone settings (gear icon) in Device List page.
2. Select Speaker Info.
3. If your UUID begins with FF31, then it is the newer version. If it doesn't begin with FF31, then it is the older version.