My customer is using MCIMX257CJM4A for their system.
And they found sometimes a port (D4) of i.MX25 comes to leave floating on their board.
The port is typically used for SPI connection(RXD) with NOR FLASH on their board and sometimes it goes to floating.
And they think that this may increase power consumption of i.MX25 for their board.
If you have any other concerns on this, please let me know.