I think I've abused a circuit board every marginal way acceptable but I would never ever solder a board that was powered up.

However, if you circuit board was powered down and you were soldering something the EEProm shouldn't be affected; assuming you have a proper temperature soldering iron and the EEProm chip wasn't beginning to melt. :)

However, working around battery backed up real time clocks can involve soldering circuitry under voltage potential. Its jut considered good lab practice to avoid - like not sitting your lunchtime pizza on the circuit boards.

aka j