What is this code about? Is there a fix?

Unfortunatley no there is not a fix for that error. The only thing you can do is try and reset the electronics by killing power to it at the breaker/fuse panel on your home for one full minute then restore power. If after that the problem persists the main control board will need to be replaced. That error means the memory can't communicate with the logic chip inside the board. The board you need for the model  ffef3054tbe can be ordered from the link below:

https://prismparts.com/products/frigidaire-range-oven-control-board-pp5351626?_pos=1&_sid=026a86edf&_ss=r