First check that allowed us to enter the recovery. So we must press VOL + and POWER at a time until we get into recovery. So we do a wipe data / factory reset and wipe cache and restart, hopefully it may have settled. If we have a Custom Recovery do these wipes and install / reinstall one Custom ROM.
If none of this works ...
What we must do is make sure we have what model (Y300-0100, Y300-0151, G510-0200, G510-0100, etc) and what was the last Update.app we installed, or if you have not installed any, what we came factory (no matter that at the time of the brick we had a Custom ROM firmware as the basis, we go, the one that matters, it is the last official installed).
Depending on the model we have of the above, proceed to search and download the appropriate Update.app our model, and build number which is equal to or higher than we had installed. You should also correspond to the company / operator of the ROM that came to us last serial or Update.app we installed.
That is, we will install our phone company Update.app (Vodafone, Yoigo ...) whose build number is equal to or greater than the build number of the original ROM, or alternatively, you can install an international Update.app provided directly by Huawei (the B175) that in most cases we will, but not all.
To install it we have to do is unzip the dload at the root of the external SD card folder (if two dload, choose the one that size deal) and then the phone off press both the VOL + VOL- combination and POWER until we get the firmware installation. If we are not leaving the installation, remove the battery 10 seconds, the back to insert and re-try.
This is the last resort there to try to revive your phone, if it does not work we have to take it to the SAT mandatory.