# Firmware on Photon stuck / freezes with flashing cyan light **URL:** \ **Category:** Firmware\ **Created:** [July 14, 2017, 9:26pm UTC](https://community.particle.io/t/firmware-on-photon-stuck-freezes-with-flashing-cyan-light/34571 "2017-07-14T21:26:53Z")\ **Posts on this page:** 1\ **Showing post:** 4
**Author:** ![incorvia](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/incorvia/32/10961_2.png) [@incorvia](https://community.particle.io/u/incorvia)\ **Post date:** [July 15, 2017, 2:00pm UTC](https://community.particle.io/t/firmware-on-photon-stuck-freezes-with-flashing-cyan-light/34571/4 "2017-07-15T14:00:29Z")
I should also ask, I've read some older threads like this one: > [@Semi-Automatic Mode Question](https://community.particle.io/t/semi-automatic-mode-question/7855): > > Hello everyone! I am using the Spark Core to control a critical system. Basically I listen to 6 inputs, then based on these inputs I fire a few relays using some other IO’s. Because this operation is critical, I decided to use SYSTEM\_MODE(SEMI\_AUTOMATIC). Now, when I power my Spark Core, my usercode runs where in the Setup() routine I set my default values/etc. Then I do a Spark.connect() and define my Spark.function(…). Now my usercode halts till the cloud is connected and then my Loop() … And they suggest: > If the Cloud disconnects unintentionally, the Core will continue to try to reconnect to the Cloud and will block execution of user code when attempting to connect to the Cloud. He goes on to say, to test: > For the unintentional WiFi disconnects, I find it's easiest to use a uFL Core and disconnect the antenna. To disable the Cloud, you have to do something like create a firewall setting in your router that prevents your core from seeing the internet. But that is hard for me to do in my current situation where I don't have access to my router. This was written though in 2014. Could this also be something that would cause it to freeze? --- _[View the full topic](https://community.particle.io/t/firmware-on-photon-stuck-freezes-with-flashing-cyan-light/34571)._