Learn how to unbrick/flash this device using sp flash tool from here
Note
Follow the instructions on how to flash the device carefully from the link above
I will not take responsibility on whatever may happen to your device.
Make sure you are downloading the exact ROM of the device you want to flash because
flashing a wrong preloder, will make the device completely dead
(can't power on, can't charge and will not be detected by a computer)
TECNO Y4 SPECS
Android 4.4.2 (KitKat)
Dimensions - 140.2 x 74.5 x 10.6 mm
4.0-inch Touchscreen, 480 x 800 , IPS 233 ppi
1.0GHz dual-core Processor
Mali - 400MP2 GPU
MT6577
1GB RAM
8 GB Internal Memory
Supports up to 32GB microSD
5 MP Rear Camera, LED Flash, Auto Focus
0.3 MP Front Camera
Dual SIM
EDGE / GPRS
WCDMA
WIFI 802.11 b/g/n
bluetooth 3.0
1800mAh Battery
TECNO Y4 STOCK ROM
Y4-G220-A1-KK-20150320
ADS HERE !!!