Phase 3 — Standing Up the “Brain” (Home Assistant OS on the ProBook)Hardest, most setback-heavy phase. Target: HAOS bare-metal on a salvaged HP ProBook 6560b (2011). Setback: balenaEtcher crashed on macOS Catalina 10.15.8 — used Terminal’s dd instead. Setback: 2GB USB stick too small; swapped in 31.5GB SIMMAX. Setback: Ubuntu 26.04 too new — froze at “Generating APT cache,” ACPI errors, black screen. Setback: Lubuntu 26.04 — same kernel/hardware mismatch. Setback: no WiFi drivers in the live session. Breakthrough: moved the ProBook to wired Ethernet at the router — Lubuntu went online, downloaded haos_generic-x86-64-18.0.img.xz. dd’d it to /dev/sda. Result: Brain is alive.Voice-satellite bring-up. Installed the official ESPHome add-on. Plugged the 4D Systems GEN4-ESP32 (chip label ESP32S3-R8N16) into the ProBook’s USB. “Plug into HA server” → “No serial ports found.” Two stacked causes: (a) USB cable was charge-only 4-wire — swapped to data-capable; (b) add-on had no USB pass-through — fixed via Settings → Add-ons → ESPHome → Configuration → Options → Edit in YAML → usb: true → Stop → Start. Log confirmed “Found serial port: /dev/ttyACM0.“Wiring: MAX98357A on GPIO 7/15/16 with VIN=5V; INMP441 on GPIO 4/5/6 with VDD=3V3, L/R grounded. YAML: two I2S buses (i2s_amp, i2s_mic), media_player, microphone, micro_wake_word, voice_assistant for the Gemini pipeline.First compile/flash: ESPHome 2026.6.4. ESP-IDF toolchain ~100 MB, ~12 min total. Bootloader preamble clean up to entry 0x403c8914, then no app log lines. RGB LED flickered cyan once, then solid red; ~15 sec later rst:0xc (RTC_SW_8914) — app called its own reset. Heap-starved init.Tried (all the same hang): esp-idf vs. arduino framework, octal/quad/disabled PSRAM, ProBook USB vs. external 5V USB-C, stripped WiFi+API+OTA-only config, BOOT+RESET into download mode + clean re-flash. Power ruled out. BOOT+RESET cleanly entered boot:0x2 (DOWNLOAD(USB/UART0)) — chip and host acceptance are healthy.Root cause. Compile log: HARDWARE: ESP32S3 240MHz, 320KB RAM, 4MB Flash. Despite the 16MB badge, actual module has 4MB flash, 320KB RAM, no PSRAM — even minimum WiFi+API exceeds that. Voice examples assume ≥8MB PSRAM. Decision: order ESP32-S3-DevKitC-1-N16R8 (16MB flash + 8MB octal PSRAM, dual Type-C, $4–10, 3-pack). 4D Systems parked as backup. Wiring stands; future swap is pull/push + change board: in YAML. Brain untouched, satellite in transit.Phase 3 setback ledger: ESPHome dashboard blank → patience, hard refresh. Charge-only USB cable → data-capable. Add-on no USB passthrough → added usb: true, restart. App-level hang on every config → hardware incompatibility (320KB RAM, no PSRAM), replaced with N16R8. Power-supply suspicion → ruled out. Silent software reset mid-init → heap budget exhausted, real fix is the new board.