existe algum arduino de 256k que já venha com o modulo de ethernet embutido? se não qual arduino usar e qual ethernet shield usar para aproveitar totalmente os 256k?
Default - 8 MByte Legacy SPI Flash main purpose is to store the firmware (or bootloader) and the latest sketch. Between 256KByte and 512KByte is dedicated for sketch storage. The download will happen automatically from the development PC, so no action is required unless there is an upgrade that is being added to the firmware.