I have managed to get ad-hoc working on my archos 7.
All I had to do was change/add some lines in init.rk28board.rc
This way the wifi application will look for the wpa_supplicant.conf file in /flash/wifi/ which is read/write
This way you can edit this file anyway and anytime you want and just turn the wifi off and on for the changes to take effect
While creating this ad-hoc enabled image I used knightdominion v0.2 custom firmware.
*Download the update.img and do the usual
*Next connect your archos to your pc. there should be a wifi folder there.
*extract the contents of adhoc configuration files.zip to this directory
* edit wpa_supplicant.adhoc.conf and put the name of your adhoc connection after ssid. (for now I do not use passwords for my connection, maybe I will try to see how it works in the future)
*u can use whatever program you like(I use SUFBS) to browse to the scripts directory in /flash/wifi and run the script files
*start-ahhoc.sh will will save the current configuration file with all your normal wifi connections to wpa_supplicant.wifi.conf then it will delete the current wpa_supplicant.conf file and put wpa_supplicant.adhoc.conf in its place.
*start-wifi.sh will just delete the current wpa_supplicant.conf and replace it with the backed up wpa_supplicant.wifi.conf
*when you are done running the script just turn off your wifi and turn it on again.
* your wifi should start trying to connect to your adhoc connection
I Hope these instructions are clear. Else I will edit it as the questions arrive.
Update.img sir dom's firmware v0.21http://www.mediafire.com/?wy94tflsb09tcss