Huawei Ascend G510 do I need to unlock bootloader and root to flash a custom ROM with CWM My sister wants me to fix her phone, an Huawei Ascend G510-0100, which is having lots of issues in the stock ROM (she's not able to call, for instance). we tried an hard reset but in a few days the phone started bothering us again (this problem presented the first time a few weeks after purchase, but she did not say that cause she thought she introduced malware...). 

We can't use our warranty since she lost the receipt and the service is 500 km from home.

So I deceded to try flashing  Android 4.4 . I flashed my own phone 3 times but I never unlocked the bootloader (Samsung Next Turbo) and root was not needed (in two of them). 

Do I need to unlock bootloader and root to flash a custom ROM in this device? I wanted to use the ClockWorkMod to flash, but I can't find an updated version for G510, can anybody link me one? 

If yes, where is the dload folder in internal storage?
Root wasn't needed,but I first tried to uninstall system apps to make the system faster, but there wasn't a really huge difference. 

I had to unlock the bootloader to flash recovery (TWRP), and now I have a custom ROM on (AOSPA 4.6).