I have a 203, was getting twitchy, so my logic went thus:

I will probably end up re-flashing to mr0, so what would happen if I added the mr0 repo, and tried an apt-get update; apt-get install mp-fremantle-generic-pr

Well the system is not what you'd call clean, has a few 203 packages installed, and required a little dpkg-foo, but it rebooted and seems fully functional. The firmware version is now 3.2010.02-08.

I'll probably reflash at some point but, I do love the apt. Apologies if anyone else posted about this.

DISCLAIMER: I have used Debian for about 6 years as my primary home OS on arm, mipsel and x86 systems. Trying the above is probably n900 suicide.