Remove the small hex screw located above the battery door and serial number on the Leaf Credo digital back. Take a small object such as a paper clip and insert into the screw hole. You will feel a small click as the paperclip falls into place, further into the back. Insert the battery while holding the paper clip position.
A small screen will appear that states:
"Repairing Firmware, please wait...
-It can take up to 5 minutes
-The display might go black or flicker
-It should restart automatically"
You will observe the defaults and firmware are restored to factory defaults. This info can be found under the Settings Menu on the touch screen (gear icon)>About section.