How we reduced core unit boot time from hours to minutes

Cloudflare investigated multi-hour boot delays on core bare-metal servers following firmware updates. The root cause was an overly eager linear search of network boot interfaces combined with vendor-imposed immutable boot order settings and inconsistent NIC strings; fixes included declaring the correct network boot interface early in the PXE stage, vendor firmware updates to expose boot-order controls, and iPXE tooling changes. These changes reduced firmware upgrade and boot times from hours to minutes and improved automation and configuration validation across the fleet.