The user interface is the controls that you turn or push or turn to select cycles and options .
This model has two of them a center and a right interface.
To change them you will remove the washer top just like you did for the main control board, then you have to remove the console to gain access to the rear of the console /control panel.
Your getting the F01 error code because electronic control board is constantly running self test on itself and other components . and once it runs across the faulty it throws up the code.
I have and YOU have already proven that the error code was in the old control board and not the new one.
THE OLD CONTROL BOARD IS BAD, the new control does not give you the F01 error so it IS NOT a component with in the unit.
If you had an other component issue you would be seeing a different error code.
Put the new control back in and move on,,, and deal with the F70 .
I do not mean to sound mean but your making a mountain out of a mole hill.
These machines are very smart and I`m not an electrical engineer to step you thru the software process.
I`m just an old appliance repair man, that once you replace a control you just throw it away and move on!!
Im going to opt out because this is going no where .
EVEN thou your original issue has been taken care of you still will not rate me .
I`m not in front of the unit , and your not satisfied with my work assisting you ,so good luck!