[Resolved] Failure: Solid White + Blue LED On What Does it Mean?

I flashed my spark core with GOOD code ( I simply changed from Degrees C to Degrees F ) and it became unresponsive I had to to a complete factory reset.

Core symptom was SOLID white ( including after power cycle ) and BLUE LED also solid.


Could you try flashing the same code again? It might be that the flash didn’t complete or data was corrupted. This shouldn’t normally happen, but might happen if power is cycled or reset button hit before the flash has completed.

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I had it actually installed in my device so I had to strip all of it out and bring it into my office. It is not an issue of powering it off while it was flashing.

As soon as I am done resetting it to factory and reflashing I can see what it does a second go around.

Still struggling to get the Spark to come to life. This is probably my 5th or 6th time where I have spent 30+minutes trying to get Spark online after an outtage. HUGE fan of Spark but holy moly does it eat up time when it goes awol.

For reference the code that I pushed when it went offline was

for(int i=0; i<100; i++) 
            total += analogRead(A6);
   temp_raw = total/100;
   temp_k = log(((40960000/temp_raw) - resistor));
   temp_k = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * temp_k * temp_k ))* temp_k); 
   temp_c = temp_k - 273.15;
   temp_f = (temp_c * 9.0)/ 5.0 + 32.0;
   request.path = "/api/v1.6/variables/"VARIABLE_ID"/values";
   request.body = "{\"value\":" + String(temp_f) + "}";

All I had changed was temp_c to temp_f for my remote reporting.

FYI 44 minutes later my spark is back online. No magic fix other then resisting it over and over. On top of the initial issue it would not do the handshake routine with my router factory resets and a bit of glaring at it seemed to work.

Code I pushed works ( all be it not correctly ).

Having the same problem now also using temperature data (Surely that’s nothing to do with it though?) I’m just master resetting it every time which obviously isn’t ideal. Did you find a fix in the end?

When you say “resetting it over and over” are you doing a power-on reset (pressing the RST button) or are you doing a factory reset?

I’ve found that if I have a weird issue with my core it’s best to just do a factory reset and reflash

Factory Reset.

My post is 28 days old now and I have discovered it is a combination of a glitchy core and bad code.

As noted it was my code and the core behaving badly together. If you start a new thread and share your code I am sure somebody can help you figure it out ( perhaps me )

Hey guys! Wanted to follow up and make sure both @Herner and @harrisonhjones got your issues resolved…if there’s a corresponding bug report that needs to be issued, let me know!


Hi Will,
Occasionally (seems to be random) my core’s RGB LED stays solid white and the blue LED stays solid blue and I have to factory reset the core to fix it. It’s happened 4/5 times on the same core with known good code.

Hey @OddieCAT, without looking at the code it would be hard for us to verify this. If you are ok with showing us what you are working on I’d love to give it a look and ensure that it is indeed not the code that’s the issue.


byte serv[] = { 172, 16, 0, 222 }; //dos
//TCPServer server = TCPServer(23);
TCPClient client;

void setup()
  // start listening for clients
    while(!Serial.available()) SPARK_WLAN_Loop();
  //  client.connect(serv,23);
    if (client.connect(serv, 80))
        client.println("We are all connected");
        Serial.println("connection failed");

void loop()
    if (client.connected())
        char c = client.read();
    //    client.stop();
        for(;;) {



// telnet defaults to port 23

TCPServer server = TCPServer(80);
TCPClient client; 

void setup()
  // start listening for clients
    while(!Serial.available()) SPARK_WLAN_Loop();
  // Make sure your Serial Terminal app is closed before powering your Core

  // Now open your Serial Terminal, and hit any key to continue!


void loop()
    char c;
    if (client.connected()) {
        while (client.available()) {
            Serial.print("It's working, promise:  ");
            c = client.read();
    } else {
    // if no client is yet connected, check for a new connection
        Serial.print(" No connection here ");
        client = server.available();
    delay (2000);


Thanks for the reply, I hope this help.

The code looks fine. Can you give me another run down of what’s happening that leads to this?

Does this only happen when flashing new code? Have you deep updated it (does it have an “update” error in the WebIDE when you look at the list of cores?)

Does it go:
Power off
Flashing green
Flashing cyan

I think it’s when I flash new code but it’s not happened in a couple of days (Thank god). Could you run me through a deep update? I don’t have a update error on the webIDE. If it happens again I’ll make sure to note down exactly when it does it. Thanks for the response.

@OddieCAT if it’s giving you a really hard time, write into support@spark.io and reference this thread. If the Core is having consistent trouble booting up regardless of what code is loaded onto it, our engineers can help you efficiently troubleshoot and decide if a replacement is necessary! We don’t want you spinning your gears if there’s an issue with the hardware.

Thanks alot @will I’ve not had a problem in the last couple of days but I will write in if does happen again.

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Solid white + blue LED happened to me recently, apparently with no reason, but I’m still investigating.
(By the way, what does it mean? The question is in the title, but I was not able to find the answer).

The real point for me is, since I have to use the core as remote data logger, is there any way to reflash a new firmware via wi-fi (i.e. remotely) when the Core goes in solid white + blue lead?
(maybe the answer is similar, maybe a bit off topic, is it possible to reflash via wi-fi when the LED is blinking red to show the error code?).