On one hand it is very light weight: less than 4k LOC and 16 kB executable (which fits completely in the first stage of SRAM), so it is easier to grasp compared

On one hand it is very light weight: less than 4k LOC and 16 kB executable (which fits completely in the first stage of SRAM), so it is easier to grasp compared to U-Boot: https://github.com/trini/u-boot/search?q=sunxi&type=Code https://github.com/trini/u-boot/search?q=sunxi&type=Code On the other hand, it has different goals and is just meant to load a blob of instructions over ethernet (faster evaluation cycle) not an entire Linux kernel with all the POSIX / UNIX stuff from SD. So you have far more control but are also on a lower level, somewhat like developing for a more powerful Arduino.