Das U-Boot alternatives
Das U-Boot is the first stage and second stage bootloader that can be loaded by BIOS or ROM from a supported boot device like SD card, flash memory, NAND, or SATA drive. If the size is an issue, you can split Das U-Boot into multiple stages. The platform loads a small SPL, which is a toned-down version of U-Boot, and the U-Boot performs at the first stage. The first stage configures memory controllers & SDRAM, and the second stage is booting load modem operating system from many devices that must be configured. U-Boot boots an operating system by reading the kernel and any other required data, e.g., device tree or ramdisk image) into memory, and then executing the kernel with the appropriate arguments.
U-Boot’s commands are actually generalized commands which can be used to read or write any arbitrary data. By using these commands, the data can be read from or written to any storage system that U-Boot supports. U-Boot does not need to read a filesystem in order for the kernel to use it as a root filesystem or initial ramdisk; it simply provides an appropriate parameter to the kernel and copies the data to memory without understanding its contents.
