The 55.6% problem: why frontier LLMs fail at embedded code

55.6%. That's DeepSeek-R1's pass@1 on EmbedBench when it gets a circuit schematic alongside the task description. 50.0% without the schematic. Best score from the best reasoning model on the first comprehensive benchmark for LLMs in embedded systems development. Cross-platform migration to ESP-IDF tops out at 29.4%, set by Claude 3.7 Sonnet (Thinking). Take a second with that. The same models that one-shot a Next.js app are coin-flipping firmware. And the benchmark only tested three boards. That