Remove all another usb/hdd drive.
Try a different file system (FAT/FAT32) flash drives.
Try plugging the flash drive into different ports.
Flash drive root /vuplus/solo4k/rootfs.tar.bz2 and etc files.
Insert the flash drive and turn on the power, if name flashing appears on the display, but nothing happens, then pull out the flash drive a little and insert it back.