Default Need Some Help..

Hi bro out there need some suggestion I just bought an unbranded z1 and I live in Singapore.Can some one advise me since I'm gonna flash the latest 290 I need clarify is it possible to flash any unbranded generic from other region? And which region is the best firmware that I should flash?Patiently waiting somebody to advise me..currently no intention to unlock the BL and Root.Mayb when time goes by most probably I just having Root but not to unlock the BL.Sorry for my bad English.