If you have not done so already, please install the Particle CLI. The command line utilities are useful not only for solving this problem but will be valuable later on, as well.
If you are using Windows, be sure to use the link to Windows CLI Installer that will automatically install all of the components instead of the more complicated manual install.
Put the Photon in DFU mode (blinking yellow) by holding down RESET and SETUP, releasing RESET and continuing to hold down SETUP while the main LED blinks magenta until it blinks yellow, then release.
Then enter the command:
particle flash --usb tinker
It’s also a good idea to put the Photon back into DFU mode (blinking yellow) and do:
Just wanted to mention that red and blue make up magenta. If you keep a sheet of white paper in front of it, the colors blend a bit better. If you're in doubt, you can post a short video and we can confirm either way.
This light seemed to be red on top and blue on bottom. This light did not resemble any example device mode. It wasn’t a mix of red and blue light, like the cyan is a mix of something, It was a clear division within that tiny led, red and blue. I’ve seen the examples of the magenta, This wasn’t it.
This is how the RGB LED is phyically constructed. RGB LEDs do have three separate "subLEDs" one red, one green and one blue.
Since the blue and the red are further apart (physically and also in regards to electro magnetic wave length) the intended mixed color of magenta may be percieved as two separate colors more prominently than the blue and green that are right next to eachother (phyiscally and also in the electro magnetic wave spectrum) and hence the resulting cyan is perceived as one colour much easier.
But with that in mind (and the tip about a diffusion sheet of paper or squinting your eyes) the intended mixed colour should become consciously perceivable.
The one RGB LED is only meant to display one colour at any given time - irrespecive of the physical creation of the colour. So be assured red+blue = magenta - at least in the terminology used in this community and the Particle documentaion.
BTW, there is no yellow in the RGB LED either, it's a combination red+green.
I had a very similar issue, and following these instructions (and all the steps required to install the Particle CLI and home-brew), did the trick. I thought my Photon was toast (always blinking SOS in red), but now it’s back to normal. Thanks.
