The Zaurus Message Board

singadriano · Joined: 14 Mar 2003 Posts: 6 Location: sydney

Hi,

to read initrd.bin on your PC (maybe people know here, but in case...)

1- compile your kernel on your PC with right stuff:
> include jffs2 in your kernel
> in "Memory Technology Devices (MTD)" Enable MTD
support as a module.
> Activate "Direct char device access to MTD devices"
and "Caching block device access to MTD devices".
> In "Self-contained MTD device drivers", activate the
module "Test driver using RAM" with MTDRAM device
size=32768 and MTDRAM erase block size=256 and
the module "MTD emulation using block device".
> In the top-level section "Block Devices", enable the
module "Loopback device support"

That is what i have in my kernel (ZLIB/MTD/JFFS2):

# Memory Technology Devices (MTD)
CONFIG_MTD=m
# CONFIG_MTD_DEBUG is not set
CONFIG_MTD_PARTITIONS=m
CONFIG_MTD_CONCAT=m
# CONFIG_MTD_REDBOOT_PARTS is not set
CONFIG_MTD_CHAR=m
CONFIG_MTD_BLOCK=m
# CONFIG_MTD_BLOCK_RO is not set
# CONFIG_MTD_CFI is not set
# CONFIG_MTD_JEDECPROBE is not set
# CONFIG_MTD_GEN_PROBE is not set
# CONFIG_MTD_CFI_INTELEXT is not set
# CONFIG_MTD_CFI_AMDSTD is not set
CONFIG_MTD_RAM=m
CONFIG_MTD_ROM=m
CONFIG_MTD_ABSENT=m
# CONFIG_MTD_OBSOLETE_CHIPS is not set
# CONFIG_MTD_AMDSTD is not set
# CONFIG_MTD_SHARP is not set
# CONFIG_MTD_JEDEC is not set
# CONFIG_MTD_PHYSMAP is not set
# CONFIG_MTD_PNC2000 is not set
# CONFIG_MTD_SC520CDP is not set
# CONFIG_MTD_NETSC520 is not set
# CONFIG_MTD_SBC_GXX is not set
# CONFIG_MTD_ELAN_104NC is not set
# CONFIG_MTD_DILNETPC is not set
# CONFIG_MTD_MIXMEM is not set
# CONFIG_MTD_OCTAGON is not set
# CONFIG_MTD_VMAX is not set
# CONFIG_MTD_L440GX is not set
# CONFIG_MTD_AMD766ROM is not set
# CONFIG_MTD_ICH2ROM is not set
# CONFIG_MTD_PCI is not set
# Self-contained MTD device drivers
# CONFIG_MTD_PMC551 is not set
# CONFIG_MTD_SLRAM is not set
CONFIG_MTD_MTDRAM=m
CONFIG_MTDRAM_TOTAL_SIZE=32768
CONFIG_MTDRAM_ERASE_SIZE=256
CONFIG_MTD_BLKMTD=m
# CONFIG_MTD_DOC1000 is not set
# CONFIG_MTD_DOC2000 is not set
# CONFIG_MTD_DOC2001 is not set
# CONFIG_MTD_DOCPROBE is not set
CONFIG_MTD_NAND=m
CONFIG_MTD_NAND_ECC=y
CONFIG_MTD_NAND_VERIFY_WRITE=y
CONFIG_JFFS2_FS=m
CONFIG_JFFS2_FS_DEBUG=1
CONFIG_ZLIB_INFLATE=m
CONFIG_ZLIB_DEFLATE=m

2- reboot...

3- Create some mtd devices:
# mkdir /dev/mtdblock
# cd /dev/mtdblock
# mknod 0 b 31 0
# mknod 1 b 31 1
# mknod 2 b 31 2

4- insert the appropriates modules:
# modprobe mtdram total_size=32768 erase_size=256 (32 Mb RAM)
# modprobe mtdblock
# modprob jffs2

5- mount the mtd device
dd if=initrd.bin of=/dev/mtdblock/0 (copy the root image to the device )

6- mount the mtd filesystem
mount -t jffs2 /dev/mtdblock/0 /mnt/mtd0

That should work...

# ll /mnt/mtd0
total 0
drwxr-sr-x 1 root root 0 May 20 2002 bin
drwxr-xr-x 1 root root 0 Jan 28 02:54 boot
drwxr-xr-x 1 root root 0 Jan 28 02:55 dev
lrwxrwxrwx 1 root root 9 Jan 28 02:54 etc -> /home/etc
drwxr-xr-x 1 root root 0 Jan 28 02:55 home
drwxr-xr-x 1 root root 0 Jan 28 02:56 lib
lrwxrwxrwx 1 root root 8 Jan 28 02:54 mnt -> /var/mnt
drwxr-xr-x 1 root root 0 Jan 28 02:56 opt
drwxr-xr-x 1 root root 0 Jan 28 02:54 proc
drwxr-xr-x 1 root root 0 Jan 28 02:58 root
drwxr-xr-x 1 root root 0 Jan 28 02:56 sbin
lrwxrwxrwx 1 root root 12 Jan 28 02:54 tmp -> /dev/shm/tmp
drwxr-sr-x 1 root root 0 Jan 28 02:56 usr
lrwxrwxrwx 1 root root 16 Jan 28 02:57 var -> /home/system/var

# df | grep mtd
/dev/mtdblock/0 32768 25260 7508 78% /mnt/mtd0

Cheers / singadriano

singadriano · Joined: 14 Mar 2003 Posts: 6 Location: sydney

How to read/mount/mofify initrd.bin

Hi there,

just one think here, there is a mistake:

blowkj · Joined: 03 May 2004 Posts: 1 Location: UK

The above works fine for and I can access the initrd,bin files. I've modified them and want to create a new version of initrd.bin. The ireverse dd command works fine but now I've increased the size I'm not sure how many records to transfer. If I don't specify the count paramater it creates a maximum size file which is not really needed. Can i use du to simply work out the size?