diff --git a/docs/v4.md b/docs/v4.md
index 437434d7..abef9a83 100644
--- a/docs/v4.md
+++ b/docs/v4.md
@@ -145,3 +145,4 @@ To enable USB 3.0, it is required to flash the USB controller firmware. It's ver
 ## Known issues and limitations
 * There may be **compatibility** issues with some motherboards (such as **HP** or **DELL**) which are the same as those that exist with PiKVM V2. Not everything is perfect, but if you have already used PiKVM V2 - our new V4 will work great and please you. If there is no image from the BIOS, you can fine-tune the HDMI settings, but it is possible that the Mass Storage devices will not be available in the BIOS. In the last case, [USB dynamic configuration](usb.md) will solve the problem.
 * While there is a Mini-PCIe slot in the V4 Plus, this was only designed with the LTE modem with USB lines in mind, therefore if you decide to get a NVME card, it will not work.
+* While the 4Plus includes a 5v USBC port for power, this is only to be used as a backup. If using this port only, this essentially turns your Plus into a Mini, the bottom board will only be powered while the top board will not thus disabling the top board which has the additional USB ports making the PiKVM expander, incompatible.