My laptop is Windows 10 Home 2004 (Build 19041.450). The Windows Update progr told me that there was a cumulative update available to install (2020-09 Cumulative Update for Windows 10 Version 2004 for x64-based Systems (KB4571756)). And then I follow the installing steps to install the update, after the installing, there were errors occurred: windows update error code 0x800f081f or 0x8007025d, I can’t fix these errors.
You can free up some drive space so you can run updates and then restart to install the 2020-09 Cumulative Update,run Windows Update again and then disconnect external hardware,update third-party drivers, you can check Device Manager to find installing errors.
If the above solution doesn’t work, you can try this solution，it will take long time to fix this windows update error：
Pleas download the media creation tool from the Microsoft website and choose to upgrade this PC.
It reinstall Windows 10 and update all the windows files, the installing process will took you more than 4-5 hours.
In fact，it depends on your laptop configurations and Internet connection speed.
After reinstalling windows 10, my video driver stops working, and then I update video driver to latest version, restart my laptop，now the monitor is displaying correctly.
Then it installed the 2020-09 Cumulative windows Update successfully，there were no any errors.
Finally I download wisepcdoctor to clean the junk files when the installing is finished.