Here is a modified set of scripts that work on my N900. FOR PR1.3 ONLY. I have tested this only with Titan's kernel-power v42. I don't know what will happen with other kernels/firmware. YMMV.

PLEASE PLEASE read the whole post before embarking on your adventure.

PLEASE PLEASE correct any errors or mistakes or misunderstanding in this post and the scripts. Thanks in advance!

DISCLAIMER:
DO NOT attempt to use these scripts if:

- you DON'T know what you are doing exactly;
- you consider yourself a NOOB;
- you feel VERY nervous of entering commands in a terminal;
- you have the SLIGHTEST fear of bricking your device;
- you will feel VERY frustrated and lost and confused if you have to reflash your "bricked" device.

I make NO guarantee of the accuracy and validity of the files and information contained in this post, and I take NO responsibilty for any loss or damage as a result of using the information in this post. Using the scripts may produce undesirable consequences on your device and may even void the warranty provided by Nokia. You have been warned.

And, BACK UP whatever is important to you on the device as always

All THANKS to Egoshin for his brilliant ideas, patience and solutions. THANK YOU!!

I've done nothing but edit the scripts such that they can now work with PR1.3,together with a couple of small fixes, in particular making bootmenu.sh executable, and correcting the root partition from /dev/mmcblk1p2 to /dev/mmcblk0p2 (this explains the failures in my previous experiments... )

My setup: see the image

Simplified steps:
1) Download and uncompress the scripts to some directory on the device, e.g. /home/user/foo
2) cd into this directory
3) Run sh M32GBinit_PR13.sh to make a duplicate the rootfs from the 256MB NAND (root previlege required)
4) Wait for the operation to finish. It may take as long as 30 minutes or maybe even more.
5) Run sh M32GBboot_PR13.sh to set up booting.
6) Exit the terminal. Reboot.
Keyboard closed => rootfs on NAND
Keyboard opened => rootfs on eMMC


Note 1: The size of the root partition depends entirely on how you partition the 32GB of space. The default is the 2GB /home partition (/dev/mcblk0p2, ext3). You may want to increase the size. See, for instance, http://wiki.maemo.org/Repartitioning_the_flash
I chosed Option 1, i.e. /home (now the complete filesystem) = 27GB ext3 ; MyDocs = 2GB vfat.
As Egoshin has emphasized, you have to repartition the eMMC before applying the scripts.

Note 2: Advantages & Disadvantages?
- No more worries about not enough space for package installations. (otherwise why do this?)
- The original UBIFS rootfs remains untouched. If the rootfs in eMMC is screwed up, you can boot into the original rootfs as a backup system to rescue the data and fix the problems in the rootfs in eMMC. BUT...
- Both rootfs are using the same /opt. Egoshin has already pointed out the inconsistency between them when packages are uninstalled on either side. SO ...
- If the /opt is also screwed up so badly, it's the perfect time to reflash.
- That said, I will definitely trade
speed for space. I personally think there won't be very obvious differences in regular use.

Note 3: For further details, see Egoshin's Post #1