The firmware package available here for download is to be flashed via SP Flashtool. It’s official Lenovo A698t stock ROM.
Note: After downloading the file, open the archive and access Lenovo A698t_S126_120710 c27eae folder to find target_bin.7z. The firmware files are contained in the .7z file- extract and flash.
Lenovo A698t ROM – Download
!Important – Password: leask
How to flash
As instructed above, find firmware files for flashing in target_bin.7z. After extracting, follow instructions here to flash https://www.leakite.com/2016/03/easy-mtk-firmware-flashing-installation.html