This message was posted on behalf of Intel Corporation
Thank you very much for your interest in the Intel Edison platform and for posting your question in the Community. We’ll be glad to help.
Regarding your question, there’s not a supported method to flash multiple Edisons at the same time or anything similar to bulk flashing, you’ll need to complete the process manually using the known flashing tools (Flashall script or Flash tool lite).
Hope this answers your question.