Sometimes I found that the unit does not wake up from sleep when the power button is pressed. So here is what I did to make it work. Its quite simple, if there's a microSD card inserted, eject it. If there's none, insert one.
I found an app called "
Wifi File Explorer", technically it allows you to make a connection from the Libre Touch to any networked computer, wirelessly. When the app runs, it opens up a port and you can use a web browser on a PC or a Mac, type in the IP of your Libre Touch with a port number provided by the app, and you can then browse and manage files on your Libre Touch right from your computer. You can also upload and download files wirelessly between the two, and thus eliminate the needs to transfer stuff by either using the USB cable or the microSD card.