Look here
http://wiki.maemo.org/Updating_the_tablet_firmware

Make sure you use flasher-3.5 and I was directed to use the combination images not the vanilla and fisaco and it worked very nicely.

can you tell me which one to flash particularly? i usually flash the rootfs with 20.2010.36-2 pr1.3

which combined image? there are two vanilla images.i ges u r NOT recommending that one.then which one?

Anybody tried installing the deb after removing existing Nitdroid?
Did it work? It was tested on a freshly flashed device last night and I haven't restored my backup so can't test it (I'm at work).

INTERNET CONNECTION required during installation.
To those who'll be installing on a freshly flashed device:
1. Make sure you flashed using either the 5GB or 8GB custom EMMC especially if you'll be installing lots of apps for your N900. (this is really just a recommendation but it will save you from frustration in the future) (Google if you don't know how.)
2. Enable extras-devel and extras-testing repository (Google if you don't know how).
3. Download NITDroid-Installer_0.2.8-7.deb provided above to the "Nokia N900" folder (a.ka.a MyDocs). Clicking it will install a Nitdroid Installer.
4. Once installed, click the Nitroid Installer. This will open an X-terminal window. Confirm whenever prompted (you want to install NITDroid using Autoinstaller, right?). This should successfully install NITDroid on your device.
5. Restart your N900 with the keyboard out.
6. Choose NITDroid on the multiboot screen by pressing the corresponding number.
7. NITDroid installed! Initial startup is very slow and touching the Android (you'll know what I'm talking about when you're there) won't instantly show the desktop. Be patient.

Note:
NITDroid is overclocked by default. Use SetCPU, which is on a link at the first page, if you want to change it. (Google if you don't know how).
Kernel Power will be installed. Please check for possible conflict with existing installations. I know an old FCamera/BlessN900 version had problems when I first tried KP46, just update FCam from extras-devel/testing.

I'm not a coder so I can't really troubleshoot, I hope those who can will try to help. The developer of the installer has done his job, let the community takeover and save him from more frustration.

trisha and luh,
this is the 8GB EMMC: http://www.mediafire.com/?5o1hkuuwhn8hh1c

and i think this one is the 5GB (not sure): http://www.mediafire.com/?j6srnaxwr3notaf

use either of the two when flashing the EMMC. extract them first using 7zip. (Google if you don't know how.) HTH

i am jus gonna ask a very dumb question here..lol...but still here it goes-

i knw how to flash and enable the other reps and evrythng...but my main question or lets say confustion is do i need to put any other files on my nokia n900??i mean do i flash it clean of evrythng and jus simply install the new installer? or do i need to put any tar. files or smthyn els??

thnx!!

u mean it will give me 5gb and 8gb respectively for application.where the default is 2gb.

i shud flash the same way mentioned in the wiki right? emmc first and then the fiasco.basically the emmc given in the link is a substitute of the vanilla img? ami i right?