Hi Invalid_username,Intel has released a new Firmware Update Tool (FUT 2.1.5) version as of August 1, 2016, which can be accessed here: https://downloadcenter.intel.com/download/18363Thanks,JE_Intel
A new version of Toolbox with the proper signing certificate will be released shortly, this would fix the download issue you have reported. We'll keep you posted as soon as available.
