550d / T2i Intravalometre Issue/Glitch

[banabon]

Hi everyone

I have recently run into an issue with my 550d/T2i and the intravalometre function. When setting the the camera to duration longer than 10seconds with the camera set to take pictures like crazy (so as to avoid any jump in the images content) my camera seems to freeze up during the write process for a peculiarly long period of time. example here http://www.youtube.com/watch?v=NWdkllmDWaQ

I recently updated to the latest version of ML but never saved a previous copy of the firmware I was using before I never had this issue before and was always happy with my timelapse results, now not so much. I would imagine this is related to the (jitter) that I have noticed appearing in the intravalometre settings which seems to vary depending on the length of the clip is there a way to remove this? Or a way of downloading previous firmware as I was hoping to do some Astrophotography for the meteor shower tonight. (I believe its in the NW of the sky tonight I am in England but would hope that it will last long enough for everyone in the North Hemisphere to see.)

Any help on this on what is causing it and how to avoid it would be much appreciated I'm not sure if this jitter function is to correct some error but I was perfectly happy with the results until this, I just hope the 550d isnt finally expiring.