Coolpad 8297l-100 E: failed to verify whole-file signature when updating through rom file? i am using Coolpad 8297l-100 E now it is getting very slow,not showing gallary i formatted it through settings but issues all remained for that i decided to root using original rome file but it gives error.

Please help me soon to resolve this issue
If flashing through recovery results in an error, it's probably because the file you are trying to flash is not intended to be flashed via recovery.

In this case, you have to flash using a computer instead.

Coolpad devices need a software called YGDP which will do the job for you.

You also need a CPB firmware.

Instructions on how to use the software can be found here