How to set up a KMBox B+ Pro for DMA cheats
USB serial KMBox B+ Pro: CH340 drivers, the PC and COM ports, and a cursor test before the loader.
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What this device is
KMBox B+ Pro is a USB serial input device that the second PC reaches through a COM port. It is simpler to set up than a KMBox Net because there is no ethernet subnet to configure, but latency and feature support still depend on the game software rather than on the box itself.
What you need
For a first test you need the following.
- KMBox B+ Pro
- The two USB cables that ship with the unit
- A spare USB mouse and keyboard for the KMBox host ports
- CH340 / CH341 serial drivers on the second PC
Info
Install the serial driver
Install the CH340/CH341 drivers on the second PC and reboot. Until that driver is in place, Windows will not assign a stable COM port, so the game software has nothing to connect to.
Warning
Don't swap the PC and COM cables
The spare mouse and keyboard go into the KMBox USB host ports, the port labelled PC goes to the gaming PC and the port labelled COM goes to the second PC. Swapping PC and COM is behind most 'the device is dead' tickets, so label the cables once everything works.
Tip
Find the COM port
Open Device Manager on the second PC and note the KMBox's COM number under Ports (COM & LPT), for example COM3, then enter that exact number in the game software. Unplugging the cable can change the number, so check it again every time you move a cable.
Test the cursor first
Use the KMBox test utility or the software's own input test: move the spare mouse and press a key, and the gaming PC should react. If this test fails, stop there, because the game overlay is not the next thing to check. If it passes but the game feature still does not work, the problem is the integration, not the box.
If the COM port disappears
Try another USB port on the second PC, avoid hubs, reinstall the CH340 driver and reboot. Swapping the cable on the COM side is a good second test, and front-panel headers are a frequent cause of dropouts.
What to send support
Send the COM number, a Device Manager screenshot, a photo showing which cable is in PC and which is in COM, whether the test utility already moves the cursor, and your order ID.
Still stuck? Open a ticket on Discord
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