Emeryth wrote:RAM can be upgraded to 64MB if you are not afraid of hot air soldering.
Just take out one chip from a 512MB DDR 333MHz SODIMM module and replace the one on-board.
Yes, more details on the compatible SDRAM chips can be found in the OpenWRT Wiki
It looks like you can replace
the 4MB SPI Flash by an 8MB (MX25L6445EM2I-10G SOP8), but this would require an SPI Flash programmer (BusPirate?) to backup and restore the Flash.
And you can also use GPIO7 and GPIO29 as a software I2C port
by unsoldering the R15 and R17 pull-down resistors: