There was a long delay in booting screen of MSI H61M-P23 mainboard when the CarPC JoyCon Exr was connected.
Firmware 111126 version solved the boot trouble with MSI H61M-P23 (B3).
(Firmware 111126 version is only for MSI mainboard, other mainboard user do not need 111126 version.)
Update the CarPC JoyCon Exr firmware to 111126 version.
You can update the firmware in the "FW" tab of JoyCon Explorer.