You must install the MediaTek USB VCOM drivers so your PC can "see" the phone in its pre-boot state.
MT6589 devices are notorious for losing their IMEI (Network Signal) during formatting. Before using an exclusive scatter file to "Format All," always attempt to back up the NVRAM or NODL_NVRAM partition using MTK Droid Tools or a similar utility. Conclusion mt6589 android scatter emmctxtnnlin exclusive
Stay safe, and happy flashing—but only with verified files! You must install the MediaTek USB VCOM drivers
: This means the "Exclusive" scatter file you are using has a different partition layout than what is currently on the phone. You must select "Firmware Upgrade" to re-partition the drive. Conclusion Stay safe, and happy flashing—but only with
Uncheck the "Preloader" box unless you are absolutely sure you have the exact match for your hardware, as flashing a wrong preloader can "hard brick" the device.