Allwinner H3 Firmware [cracked] -

git clone https://github.com/u-boot/u-boot.git cd u-boot make CROSS_COMPILE=arm-linux-gnueabihf- orangepi_pc_defconfig make CROSS_COMPILE=arm-linux-gnueabihf- -j4 # Output: u-boot-sunxi-with-spl.bin

If you dd a standard Linux ISO to an SD card, the H3 will ignore it. You need a special "boot0" image. Allwinner H3 Firmware