The only way to download a Nokia tablet firmware is being the owner of a tablet. The user has to enter it's own MAC-address to be able to download the file. To download a N810 firmware you need to have a valid N810 MAC-address.
A post on News.com describes the exact procedure to follow if you want to try this in your N800:
- Go to the N810 software download page.
- Enter the serial number for a valid N810 device. To get one of these, pick any number between 001d6e9c0000 to 001d6e9cffff. Pick any random 4 digits (between 0-9 and a-f hex) as the last 4 digits.
- Download the file named "RX-44_2008SE_1.2007.42-18_PR_COMBINED_MR0_ARM.bin."
- Download the latest firmware-upgrading software, "flasher-3.0".
- Now that you have the firmware flasher and the 2008 N800 software update in the same directory, open up a terminal (on a Linux desktop/laptop), and type:
chmod a+x ./flasher-3.0
./flasher-3.0 -u -F RX-44_2008SE_1.2007.42-18_PR_COMBINED_MR0_ARM.bin - That will unpack the software, and it may take a few seconds. Once that is done, plug the N800 into your computer, using the included USB cable, then reboot the Nokia device while holding the home button. Now execute the following commands:
sudo ./flasher-3.0 --enable-rd-mode
sudo ./flasher-3.0 -k zImage -f
sudo ./flasher-3.0 -n initfs.jffs2 -f
sudo ./flasher-3.0 -r rootfs.jffs2 -f -R - That should be it. Your device should now boot up with the new 2008 version of the Nokia Maemo operating system.