Your post is a bit unclear. Are you having an issue capturing the image or deploying the image?
When you say it reboots before its ready to deploy, is there an error message? Is this reboot happening in FOS image push or in/during WinSetup/OOBE? if the error is in FOS then capture a clear screen shot of the entire screen with a mobile phone and past the results here. The context of the error is almost as important as the error message itself.