Download Android ICS 4.0.3 Stock Firmware for Lenovo A390T smartphone from here or here. Download another Lenovo firmware from here.
Archive name: Lenovo_A390t 4.0.3 FW
Archive file size: 171 MB
Model: Lenovo A390T smartphone
Platform: Spreadtrum SC8825
Build number: sp8825eaplus-user 4.0.3 IML74K A390t_S125_130821 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.