A method and related apparatuses support booting despite deficient system resources. In one embodiment, a processing system includes two or more devices in a peripheral connect interface (PCI) subsystem, as well as instructions encoded in a machine accessible medium. The instructions, when executed during a process of booting the processing system, may determine whether sufficient resources are available for the devices. The instructions may also retrieve boot information from an extended firmware interface (EFI) environment of the processing system, and may automatically identify a device as boot-critical, based on that boot information. The instructions may also identify a device to be rejected, and may automatically allocate resources for the boot-critical device but not for the rejected device, before the processing system boots the OS, if sufficient resources for the devices are not available. Other embodiments are described and claimed.