ZTE Skate hard reset:
You can reset your ZTE device's password: Turn off your phone, then turn it on. Select emergency dial. Input *983*987# in emergency dial-up pad. It will restore factory settings and your personal data will be erased.
1. Power off the phone
2. Press and keep pressed UP and HOME and press Power for about 2-3 seconds, keep pressing when you see green droid.
3. Use Volume key to move to "WIPE DATA / FACTORY RESET"
4. Confirm option with BACK button
5. Scroll down to "Yes --delete all data" and confirm using BACK button
6. After operation press Back button once again to restart phone.

or using menu
Privacy: Reset to Factory Settings
Press the Menu Key > Settings > Privacy > Factory data reset > Reset phone > Erase everything.
WARNING: All your personal information and downloaded applications on your phone will be erased
after resetting the phone.
ZTE Skate unlock pattern issue solution using firmware upgrade image file
You can reflash your firmware from memorycard using image binary firmware.
1. First of all back up all of your data including your messages, contacts, files etc. to your PC.
2. Charge your battery for at least 2-3 battery unit!
3. Take out SIM card before ZTE Skate upgrade procedure.
4. Download ZTE Skate latest firmware image.bin file from their website.
5. Copy the whole image folder and image.bin file to your SD card.
6. Go to Menu -->Settings-->About phone-->System updates, then select Storage card updates.
7. Select OK and the phone will reboot and begins the flashing procedure. It will take about 2 minutes and the phone will restart again.
If your ZTE Skate won't boot repeat flashing procedure.