I am expecting this phone, so here I will add stuff about it.
Entry page – http://www.movilesdualsim.com/foros/tcl-m3g-snapdragon-615.788/
How to install Cyanogenmod 12.1
I haven’t tried it yet, beware of bricking the phone.
http://www.movilesdualsim.com/tema/cyanogenmod-12-1-2015-06-23-android-5-1-1-para-tlc-m3g.108147/page-17
Flash recovery – to see – http://slatedroid.info/2015/08/tcl-m3g-3s-root-flashing-recovery-tutorial-finally-comes-out/
http://www.htcmania.com/showthread.php?t=1031015
Roms
http://www.needrom.com/download/tcl-m3g-airom-1-0/
http://www.needrom.com/download/tcl-m3g-airom-1-0/
Petition for official MIUI port:
http://en.miui.com/forum.php?mod=viewthread&tid=155436&highlight=miui%2Btcl%2Bm3g