I have used a variation of Michael's methods.

I store two identical copies of the data set. A single status byte is used for the data set. It normally contains 0, which means that I can just use the first set (nothing is changing). When I update the parameters, I follow this procedure:

1. Write 0xA5 to the status byte.
2. Update the first copy of the parameters.
3. Write 0x5A to the status byte.
4. Update the second (identical) copy.
5. Write 0 to the status byte.

While this may not be perfect, it is certainly easy to determine which set of data to use on Power-up.

-- Tom Bachmann