Have you tried using the Flash Tool Lite software to recover your Edison board? You can check the instructions in here IoT - Flash Tool Lite User Manual | Intel® Developer Zone.
You can also try with the flashall script, but that would require the installation of dfu-utils and then running the flashall.sh/flashall.bat file (depends on your OS). If you want to try with this option, here you can find the whole instructions https://communities.intel.com/message/311395. I would suggest to take a look at CMata_Intel comment for a detailed explanation.