https://blog.faceutil.com/2017/05/11/%ec%9c%88%eb%8f%84%ec%9a%b0-%eb%b6%80%ed%8c%85-usb-%ec%a0%9c%ec%9e%91%ec%a4%91-files-copied-successfully-however-we-were-unable-to-run-bootsect-to-%ec%97%90%eb%9f%ac%ea%b0%80-%eb%82%a0%eb%95%8c/