U-Boot loader and related files for the RADXA Rock-Pi4C

To install this bootloader on an sdcard just do:

dd if=/usr/local/share/u-boot/u-boot-rock-pi-4c/idbloader.img of=/path/to/sdcarddevice seek=64 bs=512 conv=sync
dd if=/usr/local/share/u-boot/u-boot-rock-pi-4c/u-boot.itb of=/path/to/sdcarddevice seek=16384 bs=512 conv=sync

To install this bootloader on an SPI flash just do: 

=> load mmc 0 ${kernel_addr_r} u-boot-spi.bin
=> sf probe
=> sf update ${kernel_addr_r} 0 ${filesize}

WWW: http://www.denx.de/wiki/U-Boot