If someone has tried to flash a custom rom without backing up his stock rom, and messed up mid way by not installing custom rom. No need to worry Follow these steps
download QMobile Z4 stock rom (You need Winrar 5 to unzip it). Unzip at your PC where u can easily access it.
Then You need MTK 6589t drivers (Download, Unzip n install) attached here
and finally u need SP Flash tool (Attached Here)
Just extract SP Flash Tool from Zip file and open it from Blue icon
Click "Scatter Loading" Scatter file is placed in the folder where you extracted the Stock Rom. (Dont attach your phone to pc uptill now)
Click "Download" on SP Flash Tool software and attache your Z4 with PC by micro USB cable. Phone will be detected and Stock ROM will be flashed in few minutes. A greenish Blue circle confirms Flashing successful. Close SP Flash Tool. Detach your Phone and Re boot.