Is it possible to convert the filesystem from ubifs to ext4? because i want to install a custom rom for my smartphone (MT6572 based) i need my smartphone to be in ext4-fileformat (currently it is in ubifs) because all the ported ROMS for MT6572 are ext4-based. Is it possible to change the filesystem of a smartphone?
Doing a quick Google search it looks there are at least some TWRP recovery options for your phone so the answer is probably yes but you really have to know what you're doing as even a Nandroid backup might not restore if you mess up file system formats. Generally only the System, Data, and Cache partitions can be re-formatted. The recovery partition cannot. 

Apparently it can also possibly be done with an spflash tool. See:

http://forum.xda-developers.com/android/development/mod-repartition-internal-mediatek-t2861061