You could try following instructions on this page:http://www.archos.com/support/support_t ... g=en&#firm
scroll down a ways, where it says this:
The process for restoring the legacy ARCHOS firmware is done by accessing the recovery menu. The recovery is triggered by powering on the device while pressing the 'volume down' button. In order to install the new firmware, the "repair disk" option needs to be selected by navigating up and down the items with the 'volume up' and 'volume down' buttons and then executing the selection with a short press on the power button. Once in this mode, the device can be connected to a PC and will act as a mass storage device where the legacy .aos firmware file can be uploaded. Once this step is done, press on the power button again to launch the installation process.