5 Flash Partitioning
Linux Software Developers Kit (SDK) User Guide
38
JFFS2 root
This configuration is intended to free up RAM for applications that require a considerable amount
of memory (e.g. ssh, tcpdump). These applications cannot be run from a ROMFS configuration.
One downside is that is very hard to implement a reliable firmware upgrade process for this flash
layout. It is also more prone to file system corruption of important files then ROMFS, since
everything is stored on a single write-enabled partition.
On a MatchPort AR it would look like this:
1. Download and flash the kernel image (you can use either linux.bin or the compressed version
linuz.bin)
dBUG> dnfl linux.bin
Address: 0x4001FF80
Downloading Image 'linux.bin' from 172.19.39.1
TFTP transfer completed
Read 1605760 bytes (3137 blocks)
Must erase complete sectors (0x00040000 to 0x001CFFFF)
Continue (yes | no)? yes
......................
Flash Erase complete. 0x190000 bytes erased
Program successfully flashed...
2. Download and flash the jffs2 root image to its default location 0x400000. This has to be done
in two steps. First download the JFFS2 partition image into RAM. dBUG always loads files to
this address: 0x4001FF80. Then that RAM area can be flashed to the destination address in
FLASH.
dBUG> dn rootfs.img
Address: 0x4001FF80
Downloading Image 'rootfs.img' from 172.19.39.1
TFTP transfer completed
Read 4194304 bytes (8193 blocks)
For all platform (Single bank)
dBUG> fl w 0x00400000 0x4001FF80 0x400000
................................................................
Flash Write complete. 0x400000 bytes written
3. Validate that the kernel command line is set to noinitrd rw rootfstype=jffs2
root=/dev/mtdblock5
dBUG> show
watchdog: on
...
kcl: noinitrd rw rootfstype=jffs2 root=/dev/mtdblock5
