If VOL Up and VOL Down are pressed on boot it will turn on the serial out via the usb-c port - make sure you don't have a usb host connected.
22/12/25 - breakthrough, managed to flash u-boot to the device
- (https://github.com/dsankouski/u-boot/tree/a5y17lte/board/samsung/axy17lte) - we don't need this branch now and can just use the main u-boot repo https://gitlab.com/u-boot/u-boot
- https://github.com/osm0sis/mkbootimg.git
./mkbootimg --base 0x40000000 --kernel_offset 0x00000000 --ramdisk_offset 0x01000000 --tags_offset 0x00000100 --pagesize 2048 --second_offset 0x00f00000 --kernel ~/u-boot/u-boot.bin -o uboot-test.img