== '''Imporant note: this is for gen6 aka Archos5 or Archos7 aka IMT ONLY''' ==
== ''For gen7 aka Archos5IT aka Archos5Android there is this guide: '' == '''[wiki:SettingUpMultiRootGen7] '''
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You can either use this guide or [http://www.openaos.org/~kevin/archos_angstrom_docs/dualbootinstallation.html another one]  or if you have a hacked device you could just use [http://www.openaos.org/archives/82 an .aos image] (Don't try this on original Archos firmware, it won't work!)

For now this guide will be for the advanced users. However, we'll happily accept scripts that would automate this process though! [[BR]]
I'm going to assume you still have the Archos firmware and are running a Linux Distro on your PC, if you already have SDE installed follow all steps excluding (3.) , or simply reinstall the stock firmware and start from the step (1.).

1. Go into recovery

 * Shut down your unit completely.
 * Start it by pressing [Vol+] and [Power] at the same time. You'll see the Recovery Menu.
 * Press [Vol-] until You reach "Repair Disk", then press [Power].
 * Now attach the unit to your PC by USB.

2. Backup the hidden partition

 * run: "fdisk -l"
 * look for your device (e.g. by size) and notice that the partition does not occupy the whole disk-size
{{{
Disk /dev/sdc: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

 Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       19432   156087508+   c  W95 FAT32 (LBA)
}}}
 * Now copy the unassigned space using dd
{{{
dd if=/dev/sdc of=/tmp/archos-hidden.dump bs=8225280 skip=19432
}}}
 * Please note that you use the raw device, no partition; also the bs field is taken from the Unit output of fdisk; same goes for skip it is taken from the End field for the visible first partition.

3. Install the SDE

 * Mount the first partition on your Archos device and copy the SDE .aos file into the root folder. (DATA Partition)
 * Unmount it and press the [power] button on your device.
 * If you haven't done so yet - connect the powersupply.
 * Wait for the install to finish. This can take quite a while.
 * Once the installation is done successfully power off your device.

4. Restore the hidden partition

 * Start it by pressing [Vol+] and [Power] at the same time. You'll see the Recovery Menu.
 * Press [Vol-] until You reach "Repair Disk", then press [Power].
 * Now attach the unit to your PC by USB.
 * roll back the hidden partition image (use the same numbers like in the previous step).
{{{
dd if=/tmp/archos-hidden.dump of=/dev/sdc bs=8225280 seek=19432
}}}
 * Do not disconnect the device yet!

5. Install the SDEMultiRoot

 * Get the necessary files. ([http://www.openaos.org/wp-upload/gen6/menu-updater/initramfs.cpio.gz initramfs.cpio.gz], [http://www.openaos.org/~kevin/archos_angstrom_project/rev-0199-08-feb-2010/zImage zImage])
 * Mount the first partition (the large FAT32/vFAT one) on your PC.
 * Copy the files over into the root directory.
 ** If you want to try out kevins build gunzip it and replace the SDE rootfs.img.
 * Create a menu.lst text file in the root directory.
{{{
Archos|AVOS|/rootfs.cramfs.secure|/init
openAOS|/dev/sda1|/rootfs.img|/sbin/init
}}}
 * Unmount the partition.
 * Power off the device.
 * Start it by pressing [Vol+] and [Power] at the same time. You'll see the Recovery Menu.
 * Press [Vol-] until You reach "Developer Edition Menu", then press [Power], Press [Vol-] until You reach "Flash Kernel and Initramfs", then press [Power].
 * Wait till both files have been flashed.
 * Reboot, enjoy.

''Congratulations, you have successfully installed SDE and are able to still boot AVOS from the boot menu!''

If you have further questions or have run into problems - contact us on IRC! (#openpma)