Dirk:

I have seen some tool chains that have provision to support the on-board EEPROM via some macros and library code such that the variables in the EEPROM can be declared and accessed in C much like variables that are in regular RAM. IAR is one vendor that supports this kind of thing. Are you using the EEPROM in this manner?

If so you may want to reconsider designing EEPROM access so that it is fully encapsulated in code that you have written and you have full control over the registers that support the access to the EEPROM. This would be in contrast to depending upon some hardware access code buried with a library that you cannot directly see.

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On another thought are you sure that the oscillator to your MCU is locking into the correct frequency before the release of the reset signal?

Mike Karas