With this method you can install the box directly via usb-stick or SD card, without having to use "installtointernal".
With this method You probably brick the box.
Better prepair a SD card and try to run LE.
If LE is running from SD without problems, You can try install installtointernal, but first try to get the original ROM of Your box to be able to go back if installtointernal fails.
LE 7 is very old, there is no support from developer