Arduino IDE + megaTinyCore (development) and Curiosity Nano ATtiny1607?

[Locge]

I'm using the development version of the megaTinyCore in Arduino IDE to generate code for the Curiosity Nano ATtiny1607.
I'm not getting compilation errors but the examples do not work.
I tried Blink (compiled in Arduino the dropped the .hex onto the virtual drive). Programming seems to work but there is no blinking.
I then took BareMinimum and added the activation of the LED_BUILTIN

void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LOW);   // turn the LED on by setting the output LOW
}

void loop() {
  // put your main code here, to run repeatedly:
}

The user LED did not lit up.
I the tried to re-define LED_BUILTIN and, with #define LED_BUILTIN PIN_PB7, the binary works and the user LED turns on.

#ifdef LED_BUILTIN
#undef LED_BUILTIN
#define LED_BUILTIN PIN_PB7
#endif

void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LOW);   // turn the LED on by setting the output LOW
}

void loop() {
  // put your main code here, to run repeatedly:
}

Am I doing something wrong?
Are the #DEFINE in megaTinyCore correct for Curiosity Nano ATtiny1607? Can anyone confirm that Arduino IDE + megaTinyCore (development) generates correct code for Microchip Curiosity Nano ATtiny1607?

[Locge]

I'm adding that there may be errors in the boards.txt of development megaTinyCore-master in relation to the Curiosity Nano ATtiny1607:
The line
microchip.menu.board_name.cn1607.build.extra_flags=-DARDUINO_attinyxy7 -DLED_BUILTIN=PIN_PC4 -DPIN_BUTTON_BUILTIN=PIN_PB7
is wrong. LED_BUILTIN is wired to PIN_PB7 while PIN_BUTTON_BUILTIN is wired to PIN_PC4. They have been swapped.