[U-Boot-Users] Flash Replacement for AT91RM9200-EK

Hello List, i use a custom Board based on the AT91RM9200-EK. Now i want to Replace the Nor Flash AT49BV6416 by a larger one from Spanion. The older Atmel chip specifies 70ns Access Time, the most usual Spanion chips are slower in the 100ns Range. As i read the CPU Datasheet correct at 60MHz EBI Speed the slowest Factor 1/4 gives 67ns Cycle Time. Does anyone know, how Access Time for the parallel Flash is calculated and what Speed Grade is needed for a stable U-Boot out of it ? Could a slower (100ns) Chip be used, how can this be adjusted ? Are there any additional Parameters for the Flash Chip to care of (Burst Mode, Multi Bank) ?

Thanks Thomas