OK, first off working with SD cards is a lot easier if you use a USB2 card reader attached
to your PC and NOT the Libre Pro's USB 1.1 interface to it's SD reader.
Don't use the Libre's 'SD Card Manager', or the internal memory manager to work with
your files, it is way too limitted. For the SD card it is best to use a USB2 card reader
and your PC's file management. (Windows Explorer most likely.) For the internal memory
you do have to use the USB cable, but then use the PC's file handling programs.
If you don't have a USB2 SD card reader you can use the Libre as a reader and prepare
the SD card for the update, as described in the sticky.
What I would do first is to create two folders on your PC to hold the contents of your
Libre's internal memory and the contents of the original SD card. With the USB cable
connected your PC should have two new external Drives, with new drive letters, showing
in 'My Computer'. Then copy the contents from your Libre and SD card to the folders.
This way you can always be able to restore those contents.
Then, I would reformat both the internal memory and SD card to FAT32 and run the
optional file structure checks and automatic corrections during the reformats. This
will give you a clean and well structured file system for the rest of the update. The
Root of the SD card will also be empty and ready for the 'Firmware folder' from the
update download.
You can now drag & drop the 'Firmware' folder from your zip file program into the empty
SD card.
Now just reset and try the update again.
Luck;
Ken