To get oberhumer's python-lzo to work on Ubuntu's lzo2, you'll need to apply this patch.

Drop the generates lzo.so in the same folder as the python script, and "python unlzo.py rootfs.lzo".

EDIT: Bad news: The N950's ... unique MMC structure is apparently hardcoded into system files.
Even after setting up the correct mountpoints, Harmattan sputtered and failed, and it clobbered Maemo 5's filesystem.
Used the MeeGo Kernel 2.6.37-29.1. Needed a full reflash to restore everything.

Directions: WARNING THIS WILL CLOBBER MTD5 (aka ROOTFS) -- IT MAY OR MAY NOT CAUSE DAMAGE TO YOUR MTD1 (aka config) and MTD2 (syslog?) PARTITIONS.

(1) Run ali1234's unlzo script.
(2) Make sure a SD card is partitioned into a 2GB ext4 (p1), a 2MB linux-swap (p2) and 32MB vfat (p3)
(3) Mount and copy MeeGo CE's uboot boot files to the vfat partition. Save MeeGo's /lib/modules/{KERNEL} folder (via cp-a) somewhere on your desktop. Unmount MeeGo CE's image.
(4) Copy (cp -a) Harmattan's system to the ext4 (p1) partition on the SD card.
(5) In Harmattan's /lib/modules , remove it's kernel and the "current" symlink.
(6) Copy MeeGo CE's modules folder into modules, and ln -s the folder to "current".
(7) Edit /etc/pmconfig (!)
(8) Edit /etc/fstab (mmcblk0 is the SD card when booting from SD, so edit accordingly, and use mmcblk1p3 as the swap partition.)
(9) Unmount everything, connect SD to N900.
(10) flasher-3.5 -l -k vmlinuz-{KERNEL} -b
(11) ??? Watch dmesg
(12) Break Fremantle