Coolpad 8297l-100 E: failed to verify whole-file signature when updating through rom file?
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