MCU v2.0 firmware I2C reg 0x20 handler.

// MCU i2c reg 0x20 handler
sub_4140()
{
    int a = *(reg_0x20);
    *(reg_0x20) = 0;
    if (a & 16)
        *(0xffe23) |= 0x80;
    if (a & 15)
    {
        if (a & 1)
        {
            *(0xff922) = 0;
        }
        else
        {
            if (a & 2)
            {
                sub_3e8(1, 3, 132); // 1 and 3 on stack. all vals technically have 0x02 as high byte (0x0201, 0x0203, 0x0284)
                *(0xfff00) &= 0xFD;
                *(0xfff20) &= 0xFD;
                *(0xfff03) &= 0xFE;
            }
            if (a & 4)
            {
                *(0xfff00) &= 0xFD;
                *(0xfff20) &= 0xFD;
                if (*0xffc39 == 0)
                    *(0xfff03) &= 0xFE;
                sub_38ae();
            }
            if (a & 8)
            {
                *(0xfff03) &= 0xFE;
            }
            sub_2be(5);
            *(0xfff03) |= 1;
            sub_3e8(3, 3, 132);
            *(0xfff20) |= 1;
            sub_2d09();
        }
    }
    return;
}

// Wait loop/Watchdog timer setter?
sub_2be(u8 n)
{
    *0xfffab = 0xAC;
    for(u8 i = n ; i > 0; i--)
    {
        for(u16 j = 0x35C; j > 0; j--);
    }
}