Please refer to the below instructions.

💡 [Built-in Method]

• Connect HDMI cable to the Z12 Ultra
• Press the FUNC button on the rear side of the Z12 Ultra
• Hold down the FUNC button and insert the power cord
• Hold down the FUNC button until the Z12 Ultra logo disappears
• Select Wipe data/factory reset on the system menu
• Select Yes then it will take you back to the first screen. Select Reboot system now.