22/12/25 - breakthrough, managed to flash u-boot to the device

 * https://github.com/dsankouski/u-boot/tree/a5y17lte/board/samsung/axy17lte
 * 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`