Buildroot FAQ

What are the prerequisites to use jffs2 root filesystem?

A: You should enable the following kernel config
Memory Technology Device (MTD) support
  |
  +--MTD partitioning support
     Command line partition table parsing
     NAND Device Support
        |
        +--Support for NAND Flash / SmartMedia on AT91
           ECC management for NAND Flash / SmartMedia on AT91 (Software ECC)
File systems
  |
  +--Miscellaneous filesystems
      |
      +--Journalling Flash File System v2 (JFFS2) support
Set the variable bootargs to pass Linux kernel boot argument "command line" in u-boot:

setenv bootargs 'mem=64M console=ttyS0,115200 root=/dev/name_of_block_device rw rootfstype=jffs2'

What are the prerequisites to use cramfs root filesystem?

A: You should enable the following kernel config
File systems
  |
  +--Miscellaneous filesystems
       |
       +--Compressed ROM file system support (cramfs)
Set the variable bootargs to pass Linux kernel boot argument "command line" in u-boot:

setenv bootargs 'mem=64M console=ttyS0,115200 initrd=0x21100000,17000000 ramdisk_size=15360 root=/dev/ram0'

What are the prerequisites to use ext2 root filesystem?

A: You should enable the following kernel config
File systems
  |
  +--Second extended fs support
Set the variable bootargs to pass Linux kernel boot argument "command line" in u-boot:

setenv bootargs 'mem=64M console=ttyS0,115200 root=/dev/name_of_block_device rw rootfstype=ext2'