Question : Can anyone guide me how to download MEMO software back to N900 ?

Can anyone guide me or give me references on how can i install reinstall MAEMO OS back to the machine.

Answer : Can anyone guide me how to download MEMO software back to N900 ?

I advise you to reflash from your linux PCs using the USB cable and flasher-3.5: https://wiki.maemo.org/Updating_the_...a_FIASCO_image
http://tablets-dev.nokia.com/maemo-dev-env-downloads.php
https://wiki.maemo.org/Updating_the_tablet_firmware#Flashing_only_the_kernel_from_a_FIASCO_image