Can anyone help?

I've been trying now for days to upgrade my Vu Solo 4K box with the latest OpenVix firmware with no success. I've been using the USB method. Formatted a 2GB USB drive using the HP-usb formatter method (FAT32) as suggested. Copied all the firmware unzipped files into the root of the USB. Tried the USB stick in every USB socket on the Solo but ALWAYS it ignores the new firmware and keeps booting up into the existing old firmware (4.1.06). I've tried unplugging the Hard Drive, copying the files into Solo4K folder etc etc. Nothing works. Can anyone help? Thanks.