I tried this on my 'GPS -no internal memory' 0801 (bought from JooVu Nov 2013). The first time it came up with 'IO error' when it tried to record and seemed very reluctant to work. I tried formatting the card before I reloaded the new firmware again. I tested it and left it recording to see if it successfully overwrote the files. It seemed a lot happier and recorded OK but after something like 5 - 7 hours later it just switched itself off. I tried it again but same again. I've loaded 1202 back on (which was previously working fine) and it is now functioning well again. I'm using a Samsung 32GB class 6 card.
Any thoughts or suggestions?
I also updated my firmware (no internal, w/GPS) to this 0308 from 1202. Did it a few days ago. I used a spare 8GB card for the firmware update, then replaced the already full 32GB class 10 card. So, similar to what you did, but never re-formatted the card. So far, no problems with over writing the old files on a full memory card.
The firmware update preserved most of my setup settings, so I only had to change a few settings back to what I was previously using.