A host-side wireless interface services communications between a wireless user input device and a serviced host. The host-side wireless interface includes a wireless network interface, a host interface, and may include additional components. The wireless network interface wirelessly communicates with the wireless user input device. The host interface communicatively couples to the wireless interface and to the serviced host. When the serviced host initiates bootstrap operations via a Basic Input/Output System (BIOS), the host interface operates in a BIOS host interface mode to allow input from the wireless user input device to the BIOS during the bootstrap operations. Further, when the serviced host initiates Operating System (OS) operations, the host interface operates in an OS host interface mode, wherein the OS host interface mode differs from the BIOS host interface mode. In this fashion, the user of the wireless user input device may interface with the BIOS during booting operations prior to loading and configuration of the OS.