Imporant note: this is for gen6 aka Archos5 or Archos7 aka IMT ONLY

For gen7 aka Archos5IT aka Archos5Android there is this guide:

SettingUpMultiRootGen7

You can either use this guide or  another one or if you have a hacked device you could just use  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!
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. ( initramfs.cpio.gz,  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)