It seems despite the favicon options being no longer included under the sign-in page customization tab,  dropping icons into the root folder (MRS) works fine for every platform except for creating a home screen shortcut from Android browsers. In our testing, some but not all Android devices will pull the correct icon.

For most of the sites we host, we just declare the icon in the page head, but I just can't find any files with a head to put the code into that make any difference. 

Does anyone have some experience with making this work consistently across devices?