Access main-os on Windows Phone 10

Enable fs access on File Explorer w10 mobile

Use Interop Tools 

Interop Tools - A versatile registry app for all devices

Make sure developer mode in enabled

REGISTRY HIVE

HKEY_LOCAL_MACHINE (HKLM)

REGISTRY KEY PATH

SOFTWARE\Microsoft\Windows\CurrentVersion\FileExplorer\Config

REGISTRY VALUE NAME

Normal

NavigationRoots

REGISTRY VALUE TYPE

String (REG_SZ)

REGISTRY VALUE DATA

shell:::{679f85cb-0220-4080-b29b-5540cc05aab6};knownfolder:{1C2AC1DC-4358-4B6C-9733-AF21156576F0};C:;U: