Had an unrecoverable crash on my phone a few months ago and did not back up my data so lost everything including my Easy Debian install. Had to read through the thread again to search for the method to install the latest version. For later reference and to help my fellow noobs an overview of the steps I've used to install Easy Debian - Jessie and install Iceweasel.

Prerequisites : Up-to-date CSSU install (including extra-testing repo)

1. There is currently only 1 image from Sulu that will receive updates from Debian - so download that one. It will be supported until march 2018
http://qole.org/files/debian_jessie1sulu_armhf.img.lzma unpack it to the root of your SD card. After unpacking you should have a file called debian_jessie1sulu_armhf.img. Be sure to have at least 2.5 GB free space on the card.

2. The Jessie image used is a hard float image and power kernel needs to be installed to be able to use it.
Install "Linux kernel for power user" with the app manager.

3. Install "easy-deb-chroot" with the app manager (I also installed easy-chroot, not sure if that is needed)

4. Reboot the N900

5. Click on the Debian Chroot icon on the desktop - terminal opens with some text and it should end with "Everything set up, running chroot...."
In this environment you can install software and update the debian install.

6. The image has nano (text editor) available - nano is user friendly. You need it to change the default repository:
Type in the terminal (in the chroot environment!)
nano /etc/apt/resource.list
use one of the current active Debian Jessie mirrors.
this is mine:

###### Debian Main Repos
deb http://ftp.nl.debian.org/debian/ jessie main contrib

save the file and exit nano

7. type in terminal (in the Debian chroot environment!) apt-get update

8. type in terminal (in the Debian chroot environment!) apt-get upgrade

I got an error message after doing this:
syntax error: unknown group 'crontab' in statoverride file

I solved this with 'groupadd crontab' and after that running 'apt-get upgrade' again.

This will take a while and after it is completed the process ends with the following message:

errors were encountered while processing:
dbus
dbus-x11
E: Sub-process /usr/bindpkg returned an error code (1)

9. type in terminal (in the Debian chroot environment!) apt-get install iceweasel

10. Now hopefully everything is ready to start browsing with an up-to-date version of iceweasel for Jessie
You can use the icon that is already created on the desktop - it takes a while to start and at first it looks likes it crashes.

It is slow, but it works. Hope this is helpful for anyone. There is a ton of additional info in this thread and on the wiki*

* http://wiki.maemo.org/Easy_Debian