Lest we forget, even humble devices are rootable. In fact, the best way to get the most out of lower-end devices is to root them so you can up the ante in terms of speed and usability. The ZTE Blade, also known as the Orange San Francisco, can now be rooted with a simple app called “z4root”.

Requirements:

• ZTE Blade
• Computer
• USB Data Cable
• z4root_blade_perm_root_v2

Just follow these steps to root the ZTE Blade:

1. First, download this file: z4root_blade_perm_root_v2.
2. Next, enable “USB Debugging” on your phone. On your homescreen, tap Menu > Settings > Application > Development, then make sure “USB Debugging” is checked. 
3. Connect your phone to your computer via its USB data cable, then tap the “Turn on USB storage” button on your phone. 
4. Next, locate your phone’s microSD card on your computer and copy the file (z4root_blade_perm_root_v2.apk) you’ve downloaded into the root of the microSD card.
5. Once copied, tap on “Turn off USB storage” on your phone and disconnect it from your computer.
6. Next, on your phone, use your phone’s file manager (or download ES File Explorer and use that) to locate the z4root_blade_perm_root_v2.apk file. Tap to install it.
7. Tap on it so that it does a permanent root.
8. The phone will automatically reboot itself afterwards.
9. After rebooting, you will have successfully rooted your phone. Congratulations!

This version of z4root keeps a copy of the original su and busybox binaries and restores them if you choose to unroot, leaving no visible traces in the system folder. (unless you’ve modified /system yourself while being rooted). That means you can probably still claim warranty if necessary.

If you want to unroot your device, just open the z4root app again, then click unroot.

Source: MoDaCo Forums