BrainFPV RADIX 2 HD (30.5x30.5)

input_voltage_cells recorded as the range 2-8S, not the vendor's prose "8S max" (Stephan, 2026-07-31: "the same as 8S max as you can always go lower"). The vendor states a CEILING — see notes, "direct battery input up to 8S (35 V)" — and a ceiling is not a minimum; every other flight computer in the library records a range, and 2S is their common floor. The prose form parsed nowhere, so the power chain read this part as stating no cell range at all.

Mfr product URLs serve manual/support content to automated fetches, so specs were cross-checked at defianceRC ($109.00, lowest verified retailer; mfr-store price not machine-readable). STM32H750 @480 MHz, direct battery input up to 8S (35 V), 9V/2A regulator for the digital video unit, 8 motor outputs. No analog OSD chip - OSD rendered through the digital HD link (MSP DisplayPort); board is digital-video oriented. Mfr quotes 6.5 UARTs - recorded as 6. ArduPilot support official since 4.4.1 (fall 2023). size_classes derived 2026-08-02 from voltage, not judged: the recorded 2-8S input against the size ladder's offered cells as authored today (5in offers 4S, 7in/10in/12in offer 6S, 18in offers 8S and 12S). That reaches an offered voltage in every class, so all five are declared. Nothing else narrows it: mount pattern is the Stack chain's business and firmware base is not a size fact. Flagged estimated: no vendor publishes airframe-size suitability. Vendor re-verified 2026-08-02: direct VBAT is capped at 8S/35 V and BrainFPV warns that exceeding it with the PWR:VBAT jumper soldered destroys the board — reaching 8S is what puts this board in 18in. It is also the only board in the category with a documented alternative feed: jumper open, run from a separate supply, divider still monitoring pack voltage to 12S. Motor/PWM outputs (D109): vendor states 8 motor outputs; BrainFPV's own setup docs show S7/S8 as motor-or-servo and describe using all 8 for an octocopter.