Hello, I wonder if some of you guys could help with this issue I'm having. I started flying this quad multirotor a couple of weeks ago and it was really smooth. I tested a few battery setups and all seemed ok. A couple of days ago I tried to arm the quad and one motor didn't run. I checked the i2c cables and noticed one of them was disconnected. After connecting the cable I re-started the procedure and made a couple of flights, but this weird behavior started to happen: It looses stability and accelerates all in a sudden, and gets really difficult to maintain control. It seems to get better or worse when changing battery packs, so I initially thought it could be related to battery voltage. I lowered the battery voltage cutoff to a minimum, but it doesn't seem to make any difference. I also played with PID, lowering them, but no effects on the problem. I re-flashed 3 different firmware versions (V0_78b, V2_00f and V2_08a) on the flight ctrl board, and tried 2 different firmwares for the afro esc controllers, but nothing seems to change. Here follows my setup: Mikrokopter Flight Ctrl Board 2.0 AfroEsc 30A Axi 2820/14 motors APC 14 x 4.7 slow flyers 4S battery packs tested: GensAce 6600 GensAce 10000 GensAce 12000 Hyperion 5000 QuadroPower 6200 Here follows the link for the video of the last flight: Any comments are welcome. Regards, Marcelo.