glad to hear. And thanks for reporting back.

Thanks
Felix

you are correct MISO has changed in M5Core2 from GPIO19 to GPIO38. However you shouldn't need to modify that manually. Instead it will be taken care of when you use the M5Core2 library (instead of M5Stack library).
In the Arduino example change the include file

// #include <M5Stack.h>
#include <M5Core2.h>

and then in setup comment these lines out

//  M5.Power.begin();
...
//  Serial.begin(115200);

With the above changes I can compile and run the code on my M5Core2 (no crash). Please note though - I don't have the GBRL module so I cannot fully test the result.

In UiFlow the correct MISO GPIO should be used automatically when you select M5Core2 as device.

Thanks
Felix