Christine_ASUSI got it thank you for your help. I'm done on Android 10
Thank you for your reply. Please refer to the steps below
1. Try "the Factory Reset"
Settings>System>Advanced>Reset options>Erase all data(factory reset)
Please note that once the Factory Reset is completed, all data, apps, settings and personal information will be deleted.
2. Download V429 file via PC
3. Put the image file into the root directory, the outermost place, of the MicroSD card
4. Tap pop-up notification (p.s. if the notification doesn't come out, try re-boot)
If the situation remain the same, please provide me a video of your firmware update process.