LZ4

configname: CONFIG_INITRAMFS_COMPRESSION_LZ4

Built-in initramfs compression mode
└─>LZ4
In linux kernel since version 4.1 (release Date: 2015-06-21)  
It's compression ratio is the poorest amongst the choices. The kernel
size is about 15% bigger than gzip; however its decompression speed
is the fastest.

If you choose this, keep in mind that most distros don't provide lz4
by default which could cause a build failure.

depends
CONFIG_RD_LZ4