Multiboot is a standard specifying a file format for bootable kernels and requirements for boot loaders that execute them. The specification is targeted primarily at x86-based PCs.
Multiboot images are identified by the magic number
02 B0 AD 1B (0x1BADB002) in the first 8192 bytes of the file, followed by a 4-byte bitfield of flags and a checksum. Multiboot files may be simultaneously ELF images.
A second-generation Multiboot specification is under development.