The problem was in the 15x2 PIN BUS of the M5Stack core.
It was been necessary to adjust all pins.
Now, it is works fine.
Thanks for your help.
V1.1.2 firmare: OK
M3x16 screws: OK
GO bottom firmly fastened with the Grey core: OK
If I press the Grey core and the bottom, the RGB bar works. But not the microphone.
If I change the force direction, then the microphone works, but not the RGB bar.
When I stop the force, then the bottom doesn't work.
There is a electric problem inside GO bottom.
I will have to speak with M5Stack technical support.
I bought a M5GO bottom for my M5stack Grey. Because, I want to use the M5stack with Lego.
With IUFlow, I can use the MPU9250. Perfect!
But the microphone, the RGB bar, or B and C ports, do not work.
Is possible use this elements of the M5GO bottom with a M5stack Grey?
Thanks in advance.