Partitioning a flash card

m (minor revision for clarity on the difference between mmc1 and mmc2 devices and mount points.)
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'''WARNING: Partitioning your flash card will delete all data of the card, so be sure to back up any important data to a computer or another flash card.'''
'''WARNING: Partitioning your flash card will delete all data of the card, so be sure to back up any important data to a computer or another flash card.'''
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'''Note:''' As of 4-28-2008 Penguinbait has made a deb package that automates all of this for you.  See http://www.internettablettalk.com/forums/showthread.php?t=19639  and  http://www.internettablettalk.com/forums/showthread.php?t=20534
 
== Install the necessary packages and create partitions ==
== Install the necessary packages and create partitions ==

Revision as of 20:28, 18 February 2009

WARNING: Partitioning your flash card will delete all data of the card, so be sure to back up any important data to a computer or another flash card.

Install the necessary packages and create partitions

Note: on the N800 and N810 the filesystem numbering can be a little confusing.

  • The external card device is /dev/mmcblk1 (mounted at /media/mmc1)
  • The internal card device is /dev/mmcblk0 (mounted at /media/mmc2)

So if you plan to format the external media card you will need to replace mmcblk0p with mmcblk1p in the recipe below.

First, you will need root access.

In Xterm on your tablet, run: 

apt-get install e2fsprogs
umount /media/mmc1
umount /media/mmc2
sfdisk /dev/mmcblk0
/dev/mmcblk0p1:1,15000,6
/dev/mmcblk0p2:15001,,
/dev/mmcblk0p3:
/dev/mmcblk0p4:

This will create two partitions in a 1GB flash card: the first one is VFAT (that's what number 6 means), and the second one is LINUX_83. The size of the first one is almost 480MB (that's the meaning of the 15000), and the second one is sized till the end of the card (that's what ,, means). Partitions three and four are empty.

The arguments for sfdisk are:

  • The device node to use for the partition
  • The start cylinder on the card
  • The end cylinder on the card (leave blank to have the partition go to the end of the disk)
  • The filesystem type (complete list)

A cylinder is a 32KB block on a flash card, so 15,000 cylinders equates to 480,000KB (approx. 480MB).

Format the partitions

Once you have created the required partition table, you will need to initialise the filesystems.

Type as root: 

mkdosfs /dev/mmcblk0p1
shutdown -r now

After it reboots, then open Xterm and, as root, run: 

mke2fs /dev/mmcblk0p2
shutdown -r now

Mounting the partitions

The VFAT partition will be mounted by the system automagically at start-up. To mount the EXT2 partition we need to load the kernel modules, so open Xterm and, as root, type: 

insmod /mnt/initfs/lib/modules/$(uname -r)/mbcache.ko
insmod /mnt/initfs/lib/modules/$(uname -r)/ext2.ko
mount /dev/mmcblk0p2 /media/mmc2
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