Mounting a JFFS2 Filesystem on Linux¶

Steps and debugging notes for mounting JFFS2 flash filesystems.

This English edition keeps the original illustrations and reproducible command or configuration examples.

Commands and configuration¶

http://git.infradead.org/mtd-utils.git

cat /proc/mtd

dev:    size   erasesize  name
mtd0: 02000000 00020000 "mtd_partition"

flash_erase /dev/mtd0 0 0

mkfs.jffs2 -d /data/rootfs -o jffs2.img -n -e 8192 -s 256 -c 1024

nandwrite -p /dev/mtd0 jffs2.img

mkdir -p /mnt/qspi

mknod /dev/mtdblock0 b 31 0

mount -t jffs2 /dev/mtdblock0 /mnt/qspi

mount | grep jffs2

zcat /proc/config.gz | grep CONFIG_JFFS2_FS

CONFIG_JFFS2_FS=y
  CONFIG_JFFS2_FS_WRITEBUFFER=y

cat /proc/mtd

dmesg

Practical notes¶

Test each change on a recoverable target, keep logs from the boot or failure path, and record the exact kernel and userspace versions used in the result.