B402 Stuck after Firmware Upgrade

Firmware
5

Hey thanks for that ScruffR, I had accidentally copied out the wrong script from that thread. Okay so using the corrected sketch (below) allowed me to get serial transmitting.

#include "Particle.h"
#include "dct.h"

SYSTEM_MODE(SEMI_AUTOMATIC);

void setup() {
    // This clears the setup done flag on brand new devices so it won't stay in listening mode
    const uint8_t val = 0x01;
    dct_write_app_data(&val, DCT_SETUP_DONE_OFFSET, 1);

    // This is just so you know the operation is complete
    Serial.begin();
}

void loop() {
    Serial.println(".");
    delay(1000);
}

Every time I flash the following however, I get a red SOS.

#include "Particle.h"

STARTUP(System.enableFeature(FEATURE_ETHERNET_DETECTION));

void setup() {
    Serial.begin();
}

void loop() {
    Serial.println(".");
    delay(1000);
}

EDIT: Attempting to use the Particle App to setup the ethernet results in an SOS also. Perhaps an issue with this firmware and Ethernet?