Ensure you download the version specifically for your chipset (Mediatek Helio G85). Using the wrong firmware can "brick" your device. Flash Tools: For Mediatek devices, updates are often applied using the SP Flash Tool
If you are still waiting for the notification, be patient. Tecno has confirmed that 100% of Spark 8 Pro units will receive the "new" Android 12 build by the end of this quarter. tecno+spark+8+pro+android+12+update+download+new