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5.0.0 — August 2026

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@STRML STRML released this 08 Aug 15:32
· 1 commit to main since this release
v5.0.0
11895f5

5.0.0 — August 2026

The first release on the GCU Gen 3 — a development cycle's worth of shift-smarts, logged and tagged so the box tells you what it did. The GCU Gen 3 now drives the brake light, every auto-downshift refusal is explained in the logs, and shift traces record exactly where the shift drum went.

Install instructions: GCU Gen 3 — Flashing Firmware

This is a CAN (Gen2, drive-by-wire) build only — the zip contains no KLine firmware. The GCU Gen 3 will support KLine cars, but that path isn't out yet.

What's in this release

  • The GCU drives the brake light. Brake pressure from the dash's brake channels switches the brake light on and off. Failsafe is fail-bright: if the dash goes quiet or a sensor reads out of range, the light comes on rather than staying dark. A bench mode (BRAKE_TEST) lets you force the light on for wiring checks.
  • Auto-downshift refusals are visible. Hold the down paddle and the box walks down toward redline. Every time it declines a shift — revs still climbing, wrong conditions, no fresh data — it now says why, in the logs and on the dash. No more silent "hold did nothing."
  • Shift logs tell the truth. Every upshift records where the drum actually went (not just "it shifted"), shift success/fail counters are readable without a dash, and twice as many shift traces survive an outing.
  • Settings saves no longer lie. A failed write to flash now reports failure instead of saying OK.
  • Gentler neutral finder. The progressive neutral pulse is configurable (5/10/20/30/40 ms) instead of one fixed value.
  • Flasher improvements. It enters the bootloader on its own before flashing, and the Sessions viewer got a proper dialog and scroll-pause.

Flasher note

This release contains .bin files for the Feather-M4-based GCU Gen 3. The GCU Gen 3 flasher is built into the same app; connect via the USB-C piggyback on the harness (dealer-installed if your car doesn't have it), power the car on first, and pick release_CAN_feather-5.0.0.bin.

Downloads

  • Rush SR — GCU Firmware Releases (this repo): rush_GCU_5.0.0.zip below.

Install instructions

See the owner's manual — GCU Gen 3 for full flashing, telemetry, log-pulling, and troubleshooting steps.

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