The Stable update OS4.0.0.8.XGNCNXM has been officially released for Redmi K100 Pro Max / POCO F9 Ultra (codename is songyuan). Before updating, please make sure you have downloaded the exact ROM matching your Xiaomi phone/tablet. In Fastboot mode, you can check model code by typing fastboot getvar product in cmd/shell.
The firmware files posted here are all official Xiaomi MIUI or HyperOS ROM, xiaomiROM.com do not own and never modified those firmwares，you will always download the file from Xiaomi server.
You may interest in those contents: Redmi K100 Pro Max / POCO F9 Ultra ROM Topics Xiaomi Devices Index
Download Redmi k100 pro max (songyuan) China HyperOS OS4.0.0.8.XGNCNXM Recovery ROM with Android 17.0. Firmware size is 9.9 GB.