Trying to upgrade the firmware on a X670-G2 switch by using the USB port. I tried a couple different USB sticks, formatted FAT and FAT32. The command: show memorycardshows the flash drive is indeed present. Running the command: download image memorycard according to this GTAC article: https://extremeportal.force.com/ExtrArticleDetail?an=000081794
...results in the error: Error: "Failed to download image - Image signature cannot be validated." I know this file works, I just used it on other summit switches to upgrade via TFTP. What could be the issue via USB?