i would suggest you start with the vanilla Maemo until you feel comfortable with X-Terminal (apt-get, aptitude, dpkg and all that sort of rubbish) (tip: install mc (midnight commander) if you want to dive into X-terminal (which you should probably do BEFORE tackling CSSU)) personally i have two N900, one which i use as my mobile phone (/ pocket computer) and the other as a testbed for, well, lately i was testing the most recent version of Kernel Power, battery patch, speed patch and the like... so, i though after reading "that other thread were everything is explained..." (that about summarizes the discussion over there ) that i would throw CSSU into the lot; the device was working without problem PRIOR to CSSU; after installing CSSU, the only thing that i could do was... reflashing thus, my advice (after over 1 1/2 yr of N900 and over 15 yrs of Linux / GNU) stick to vanilla for now btw, welcome to the N900 community and lot of fun with your device EDIT: in all fairness, even while re-flashing it, i thought that i should give CSSU... a fair chance on a "clean" device, that is without all the other things; especially FCAM, considering that CSSU also updates the camera feature.... have to look into that then again, if i have to choose between CSSU and FCAM, i guess i'll go for FCAM @ least it has (described) features, whereas CSSU...
before you do anything you should install backup menu and make a full backup of opt and root http://talk.maemo.org/showthread.php?t=63975 once you have this installed you can easily restore your system to the condition it was in when making the backup without flashing also use the power search on the right under the 2 banner ads the forum search sucks