STM32F205. When generating a new cubeMX project with I2C1 (master) enabled, I2C1 transmission does not work.

[GRaf.1]

when trying to call HAL_I2C_Master_Transmit returns HAL_ERROR. If I2C2 starts, then everything works

[waclawek.jan]

Debug as usually- find out where in Cube the error originated, check hardware connection, pull-ups, observe waveforms on the SDA/SCL pins using oscilloscope and compare them to the working case, etc.

JW