Hi. I'm in need of some advice. I'm helping a friend add a prusa mmu2 to his cr-10s. His using the skr1.3 board with tmc 2130 drivers and the stock cr-10 display. So the mmu is connected to the tft port (aux1) and the part that we have a problem with is enabling a serial port for the skr in marlin 2.0. I've read somewhere that the tft port is apparently identified as serial port 0. So in config.h I defined SERIAL_PORT_2 as 0 and later in configuration advanced settings I set the mmu serial to SERIAL_PORT_2. And the weird thing is that when we turn the printer on configured as such, the display won't switch on and from what we can tell the skr doesn't boot up properly. However when we unplug the mmu for booting and then plug it back in, the printer works. The mmu just doesn't. So we believe the display somehow interferes with the mmu. I'm not an expert but aren't those displays using SPI to communicate? SPI and Serial are two separate interfaces so they shouldn't influence each other right? Anyways. I'm not sure at this point where the problem exactly lays. The thing I'm not sure about is enabling the secondary serial in marlin for the skr 1.3. I know how to do it for a regular AVR boards, it's the skr I know nothing about. In general. How do I set it up to work with any serial device? Not necessarily the mmu. Is the tft port indeed port number 0 and can it interfere with the display? And are there any additional steps I need to take?