Download Android 4.2.2 Jelly Bean stock firmware for Koobee T600 smartphone from here or here.
Archive name: Kobee T600 fw
Image: 酷比T600双核 / A99.KB.V2.09.201306091330
Archive file size: 340 MB
Support: Mediatek MT6577
Project: hsimobile17_twn_td_jb
ADS HERE !!!