I have Huawei Ascend Y330 with Android 4.2.2. I was wondering what is the best approach to root my device and what is the best way to flash custom ROM with higher Android version (4.4 or even 5.0 if possible)?
I saw a lot of links on the internet, but all of them are not about Huawei Ascend Y330. I saw even strange guide how to flash my device to Android 5.0, but I don't think it's possible.
Based on this thread you can root the device using KingoRoot (see here).
As for custom ROMs, it seems the device is not popular enough amongst hobby developers to have attracted someone with the time and skills to create a custom ROM. It seems you might have to wait for custom ROMs, or ask somebody over at Modaco or XDA if they could perhaps try creating such a ROM.
Custom ROMs are almost always hobby projects, so if your device is not sold very much or nobody with the required skills for building a ROM has bought one, you are out of luck.
This post contains a link to a few articles about running a modded ROM on your device (source). This is the stock ROM with some added features/functionality. Please keep in mind that this might void your warranty.
Here are the contents of the pastebin mentioned above: (by C.G.B. Spender at XDA-developers)
Stock UK ROM (takes forever to download, but handy if you brick the phone)
To unlock bootloader
To install CWM Recovery (it can't mount external SD because it looks for it in wrong place, but flashing etc works):
Rooted Stock ROM
Rooted stock material themed
Note: You should always make a full backup before switching/modifying ROMs, just to be sure! Some devices require a factory reset when rooting or upgrading to a different ROM.
Try KingRoot. It definitely works for me every single time. Unfortunately, it is not available in Google Play Store so you have to obtain a .apk file from internet. (sites like apk4fun might have some of its versions ). The application contains code for by-passing android security - do not worry, this is actually for rooting purposes and gaining extra ordinary permissions; these permissions let you remove system apps like FM Radio, Wallpapers, but only if you want. Try to obtain the latest version available.