@c0rnelius I would like to report back with the news of full success: I have updated cmdline.txt to start with: console=tty1 console=ttyAMA0,115200 earlycon=pl011,0x107d001000,115200n8 And also added the following to config.txt: usb_max_current_enable=1 enable_uart=1 dtparam=uart0 dtparam=uart0_console dtparam=pciex1 dtparam=pciex1_gen=3 max_current_enable=1 dtoverlay=disable-wifi-pi5 dtoverlay=disable-bt-pi5 All this with the HAT+ (in the picture above) still connected. The early boot console also works, and I also get a login prompt, which is all I wanted. After this I tried replacing ttyAMA0 to serial0 in cmdline.txt, to see if there is any difference, but they both seemed to work in the end.

Not exactly. CH341 is the connection of my printer (Klipper), and here all right: [30663.467079] usb 3-1: new full-speed USB device number 3 using ohci-platform [30663.665820] usb 3-1: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64 [30663.665867] usb 3-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0 [30663.665891] usb 3-1: Product: USB Serial [30663.668223] ch341 3-1:1.0: ch341-uart converter detected [30663.680198] usb 3-1: ch341-uart converter now attached to ttyUSB0 Accelerometer board: [30617.149526] usb 4-1: new full-speed USB device number 22 using ohci-platform [30617.358206] usb 4-1: New USB device found, idVendor=1d50, idProduct=6177, bcdDevice= 1.00 [30617.358227] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [30617.358235] usb 4-1: Product: rp2040 [30617.358242] usb 4-1: Manufacturer: katapult [30617.358249] usb 4-1: SerialNumber: E6647C7403433637 It looks like Armbian needs a driver. When connecting this card to Windows or Mac, the device is identified as a serial port.

I'm referring to this board: https://www.vividunit.com/Main_Page tonymac32 has a branch for it on https://github.com/Tonymac32/build/tree/vivid but it hasn't gotten updated in a while and is not merged into the main repo.

@AndroidNewbie, what kind of help do you expect to receive? @Ducdanh Nguyen, are you sure it was my modified update.zip (hint: open it with any archiver and see for file "wipedata.flag" - is it there?)? Are old settings and apps stays in place after flashing? Are update.zip located in root of sd card? If all answers is yes, then try to update using usb flash drive instead of sd card.

That's an interesting question. The chip itself seems to communiate via spi or i2c. Since USB cannot do that they put a raspberry microcontroller (RP2040) on it to handle this. The communication then uses a simple serial connection with the ch341 chip. I assume the klipper thingies can handle this by themselves automatically while when connecting this to a different device, you have to come up with some way to communicate with this board.