Get Android Gingerbread 2.3.6 Stock Firmware for Lenovo A308T smartphone from here or here. Get previous firmware from here.
Update file name: Lenovo_a308t 2.3.6 fw
Image: Lenovo_A308T_SD_SJJL_20150313 & Lenovo_a308t_sjds_20140313
Archive size: 277 MBPlatform: Mediatek MT6572 Build number: lcsh72_t_gb3-user 2.3.6 GRK39F eng.zhengbaojiang.1383200288 release-keys
Caution: Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data.