diff --git a/README.md b/README.md
index a6a9247a..a38ca84a 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,9 @@ or in a [Secure Folder](https://www.samsung.com/uk/support/mobile-devices/what-i
 or as second instance (MIUI), or as Parallel app (OnePlus), or as Xiaomi dual app
 because the Android VPN service too often does not work correctly in this situation, which can't be fixed by NetGuard.
 
+NetGuard is not supported for internet connections via a wire, like ethernet or USB,
+because the Android VPN service often doesn't work properly in this situation.
+
 Filtering mode cannot be used on [CopperheadOS](https://copperhead.co/android/).
 
 NetGuard will not work or crash when the package *com.android.vpndialogs* has been removed or otherwise is unavailable.