The CM10 ext4 issue is when you flash a CM10 custom kernel rom and select format /data & /cache to ext4 in the bootmenu. Only custom kernels can use the ext4 file system, so what happens is you format them as ext4, install CM9, and it doesn't load because it can't mount /data and /cache to write them because they're on an unsupported file system. The only things you can do are reinstalling CM10 and formatting back to ext4 of flash the sbf in extreme cases. Its not dangerous at all, just very annoying if you forget to format back to ext3 .
Excellent! Thanks!
Im using cm10.1 just to try, its been a long time since the last I did it.
I hope I dont get any problem going back to my nandroid MIUI, but after 2 weeks of using MIUI, im going back to cm7 because that MIUI rom Im using drains battery very fast.
A question: Can I copy that little tuto you posted on how to port a rom from defy to bravo?
You'll have all the credits of course, its just to guide for new users, so they find that tuto and they can do the port for their own!