If key programer CN900 screen became black and white . Please check follow ways how to fix it:
Step 1: First connect CN900 Key Programmer with computer and power by USB wire
Step 2: First download : CN900_LOADER V3.10
Then decompressing file and save it
Step 3: Click .
You will see in front of Fast there marked hook
Step 4： Remove the Hook in front of Fast.
Step 5： After remove the Hook in front of Fast then press Update button. After then CN900 Key Programmer and update with computer together.
Step 6： After key programer CN900 finished update with computer then will recover as follow:
Remark 1：If update one time the CN900 auto key programmer still not recover then try as above ways again and again till it recover.
Remakr 2:If during update CN900 Key Programmer and appear a window which need you choose COM port. Then you need to choose a correct COM port. If you do not know which is correct COM port then operate as follow steps:
First right click my computer and choose property
And then choose Hardware.
And then choose device manager
And then find port （COM and LPT） and click + then will see follow ports
And then take CN900 USB wire out from computer then check the port （COM and LPT）again:
Checking the difference between connect with CN900 USB wire with computer and take out CN900 USB wire from Computer:
Then you will see when connect with CN900 USB wire with computer then will see .
After take out CN900 USB wire from computer then disappear.
So you need to choose .
Notice：When choose COM port not must be . Different computer have different case. It depend on that when you connect CN900 USB wire with computer and take out USB wire from computer which port ( COM) appear and disappear therefore that port (COM ) you need to choose.