I sent my phone for repair because of this, they updated the firmware, and sent it back with a note that phone had been tested. The whole thing took over a month. I wrote about it in different thread. The phone came back and the flickering was still there. I told them this and they said that I should apply for another RMA. Thank you ASUS Service Centre UK. I made an official complaint about service quality using the online form and guess who responded, the same person I was talking to before. This is how things work there.