The link you have been looking for is right here in this same forum. I have a brand new 8820 and will install it this afternoon. Look under "General 8800 Series Discussion" for a link that includes the following:

141381-latest-os-8820-4-5-0-72-4-5-0-52-multilanguage

Let me know how it works out if you decide to download before I do. Enjoy.