So I recently had an occasion to try this out and it seems N9 doesn't work with flasher's boot parameter.

Fortunately Coderus gave me a clue which lead me to making a Rescue CD for N9 (and N950). Here is more info:
http://wiki.maemo.org/N9/N950_Rescue_CD

Of course if you happen to already have Debian as your main system (I have my on VirtualBox) then you could install flasher and download smaller rescue images (available on MeeGo wiki).