My recent internal error 0x2000000 was an " ISR Flood on pin 55 " I think it was caused by multiple parameters referencing Pin 55 including AUX3 as a PWM and AUX6 as GPIO CAM_FEEDBACK_PIN, Relay2, SERVO 11. Warning message came up as soon as Camera was activated. Went into Failsafe mode and RTL. More info and logs can be found here.