As in title, one of esc's catch fire mid-air and I've been lucky to land without much problems.Drone builder removed original esc sleeves but I found that mine esc's are maytech 85A opto HX. Ordered replacement flashed with SimonK firmware and I found that during motor arming new esc make different sound so I am assuming that my old esc running different firmware. If someone maybe can recognize motor arming sound that will be brilliant. I'm not sure if it's possible to read one of old esc's to find which firmware and settings they are running.I guess Not. I have two options: -Find what firmware old one running and flash my new one with it.( simonK looks little bit more throttle responsive -Flash All esc with SimonK or BLheli (I am bit worried that I may brick my old esc doing that) What you guys thinking? Which esc firmware are you running and with what settings? My motors are kopterworkx kw10 (similar to Tmotor 3515) and flight controller Wookong-m Here is video how both esc's sounds and perform: