Solved
Hi Teseo liv3F on I2C sometime stall (and on UART too), i ask for a report each second, randomly about each minute i2C tx stop for 2 to 10 seconds (sometime more) and resume.
I suspect a low power setting.
Tested on STM32F746Disco and on Arduino https://github.com/stm32duino/X-NUCLEO-GNSS1A1.
