My phone is experimenting some similar issue
I tried to change the recovery in my cubot one (the grey one), supossedly it has the mt6589t SoC, but every try failed, then I thought to change the firmware (the firmware the phone had was G800_CUBOT_D1_V1.3_"some_number_here"_MJK), with the firmware G800_CUBOT_D1_V0.8_20140124_MJK, i employed the SP tools without problem, the download was succefully, the i put the battery on again, then i switched it on, the telephone started, the screen lites on, but the screen keeps black, it sounds like boots normally, even the unlock screen sound normal, but there is no image in the screen, I've looked for the newer firmware everywhere but I did not found it, somebody could help me, please!!!
The firmware I used to flash the phone succesfully was the cubot one turbo available in the needrom page. Maybe the newer versions of cubot one have a new graphic chip or something different.