Hi khoanvp,

It sounds like the S20SDtransfer has run multiple times - probably after a new SD card was inserted into the Warp.

How this script works is that it will automatically attempt to run when the Warp is booted. (This removes the necessity to ever call it manually.) If it detects a SD card it will format it, copy files to the SD card and remove these same files from the Warp. It finally creates symbolic links to the SD card. This procedure happens one time and subsequent runs detect a SD card with FreePBX files on it and abort.

As you discovered yes it removes files so it is not easily reversed.
Once the process has occurred it is generally good practice to never remove or replace the SD card.

At this point I would recommend reburning only the 'persistent1' partition on your Warp and see if this can recover your FreePBX image.

Hope this helps.