Board management controller firmware emulation

Technologies are provided for running multiple firmware instances in a board management controller (BMC). A BMC can be configured to execute a first BMC firmware natively and to execute a virtualized second BMC firmware in an emulator. The virtualized second BMC firmware can be an instance of an older BMC firmware, and the first BMC firmware can be an instance of a newer BMC firmware configured to use the emulator to delegate control of hardware components it does not support to the instance of the older firmware. As the newer firmware is updated to support additional hardware components, the instance of the older firmware's control of those components can be disabled. BMC commands can be received and routed to the multiple firmware instances that support them for processing.