I had that once. I fixed it by doing the following: - i used Maemo-flasher to disable the watchdog functions - i booted the N900 with watchdogs off, - i pressed [cntrl][shift][X] to open Xterm, - i replaced the broken transitions.ini with a backup (hope you have one...) - re-enabled the watchdogs with maemo-flasher and now it works again. For more info on what to do, and how to do it look here link more precisely MohammedAG's post. For info on Maemo-flasher check the maemo wiki. But be VERY carefull, and make sure know what you are doing! Good luck!