I downgraded to the older or previous 2.7.0 version and voila, it flies like a champ again. So after upgrading to the latest firmware update on my p4, I noticed that the drone wasn't flying properly. Slow compared to what it was before and some intelligent modes aren't working properly. And the worst part is it lost the ability to RTH (return to home). It will just ascend to its maximum limit of 394 feet and just hovers there. And in any case that the drone is out of sight, there's a big possibility that she will get lost. Or worse, cause an accident. I've consulted with the forum and got some probable advices and I am grateful for that, but unfortunately, none has worked with the p4. Until I read from somewhere about the same problem and has found the solution by just downgrading from the latest firmware. Something I have never thought about. Tried it and it worked. The drone flew like how it should and rth worked flawlessly again. I had to re-calibrate the imu after the initial test because I noticed the instability while hovering. Everything is working properly now and thanks again for the advices from the members. (The versions may not be proper as I typed them but you get the point).