Hi guys, I have a Galaxy S5 and I have a much worse problem than just screen flickering... i have a work around too. I am postiong this here hoping this might help you guys in figuring out a little more about what is causing the problem. Let me explain it.
Like everyone my screen flickers at low brightness, or is about to turn off the screen "screen timeout" and when I place a call it was like this for almost a month and then it became worse. If it lock my phone or the screen times out, I cannot turn my screen back on. The phone works normally, the touch screen works and all the apps work fine but you cannot see anything (wonder how I know things are normal? I can make a call or launch an app by guessing there position on screen) later one day the screen turned on and I immediately installed "host for Samsung" by TeamViewer and started to control my phone from my PC. Then I saw that my screen some times can be turned on. So, I obesrved what is causing it to be able to turn on. The answer strangly is heat. Right now I am posting this from the same phone still with the same problem. If I heat my screen with a hair dryer or small room heater for 3 to 5 mins I can 100% be able to get me screen to work and so to further investigate I ordered some tools from ifixit. Right now I am waiting for them to be delivered.
Hope this helps both you guys and me too.
Cheers