You could use the SRAM as a limited buffer for lost web updates. For example my ADSL2+ connection can get very unstable and loosing updates while the connection is offline gets very real, so buffering the lost updates would be advantageous.
Also retrofitting the SRAM on a piece of proto board would be pretty straight forward. From what i can see you could tap the SPI lines off the Ethernet module and go straight to a spare I/O line on the ATMega for the chip select
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