MicroPython script to let a Starlight Wii boot, replacing the serial connection to the controller select board

boot_starlight.py

from machine import Pin, UART
from neopixel import NeoPixel

# RGB pin for RP2040-Zero
rgb = Pin(16, Pin.OUT)
np = NeoPixel(rgb, 1)
uart0 = UART(0, baudrate=19200, tx=Pin(0), rx=Pin(1))

red = (10, 0, 0)
green = (0, 10, 0)
blue = (0, 0, 10)
black = (0, 0, 0)

while True:
    np[0] = blue
    np.write()
    state = 0
    while True:
        b = uart0.read(1)
        if b is None:
            continue
        print('got', b.hex())
        if b[0] == 0xFF:
            break
        if b[0] in (0xFC, 0xFD, 0x97):
            np[0] = black if np[0] == green else green
        else:
            np[0] = red
        np.write()
        result = bytes([state ^ 0x6A])
        print('sending', result.hex())
        uart0.write(result)
        state = (state + b[0]) & 0xFF