Hi,
I'm hoping someone can help me with upgrading from 1.2 to 1.3 w/ Nitdroid and multiboot installed. My question is, is there any way I can upgrade and keep my settings and tweeks without doing a complete reflash of everything? Will flashing the fasco image only keep my settings as they are or will I have other problems? I have flashed the phone from 1.1 to 1.2 so I know what to expect but not sure about having Nitdroid and multiboot installed and keeping all the tweeks and settings I've made. What can I do and expect?
Thanks in advance.

Yes there is.
Perhaps there is some easier way but I have done it some weeks ago this way:

1 - you have to update the vmlinuz-2.6.28-omap1 located in /boot/multiboot to PR1.3.

Download
RX-51_2009SE_20.2010.36-2_PR_COMBINED_MR0_ARM.bin
from

http://tablets-dev.nokia.com/nokia_N900.php
( this is the standard kernel )

Download and install the latest version of the Flasher for your PC
http://tablets-dev.nokia.com/maemo-d...-downloads.php

Execute in your PC (credits to OptX):

Rename the resulting zImage file to vmlinuz-2.6.28-omap1

2 - Then you have to update the kernel modules located in /lib/modules/2.6.28-omap1

Download the modules from:
http://repository.maemo.org/pool/mae...+0m5_armel.deb

I didn't install this deb but instead i did extract the 2.6.28.omap1 folder from it.

3 - Last you have to replace the vmlinuz and the 2.6.28.omap1 folder in your N900

I did that multibooting in powerkernel and using ssh to replace the existing file and folder in N900 with the new versions in my PC.
Check the file atributes / permissions before and after copying so to be sure they keep unchanged.

As the name of the vmlinuz file is the same there is no need to change the multiboot item that should exist in /etc/multiboot.d

After rebooting in to omap1 and verifying everything is ok i installed the latest powerkernel46 in a similar way - copying the kernel power boot image and modules to my N900 and modifying the multiboot item.

That worked in my device. I hope it also works in yours but do it at your own risk.

Good luck.