Hello friends. I'm having difficulty with the work via a I2C interface using the STM32 HAL Library. Microcontroller STM32 F205RG. The project generated STM32CubeMX. The problem is this: in debug mode or after programming, followed by a soft reset turns to work correctly with I2C - no error! But after turning off the power of the microcontroller, firmware crashes on the stage of sending or reading data on the interface I2C. What is my fault ?