# Firmware Update

A V6 board has two MCU devices. Each MCU manages two CAN/CAN FD and two RS485 interfaces, so program both devices separately.

## Select the Correct Release Package

Identify the MCU platform before selecting firmware. Firmware for different platforms must not be mixed.

| Platform | Release directory | Latest releases |
| --- | --- | --- |
| STM32G473 | `firmware/g473/release/` | `spine_v6_v66_release` |
| G0A | `firmware/g0a/release/` | `spine_v6_v68_release` |

Use the matching `*_release.bin` for production or field updates.

## Important Warning

**Do not perform a full-chip erase.** High Flash addresses may store device identity, authorization, communication settings, and batch tasks. A standard firmware image cannot restore data removed by a full erase.

For G473, program from `0x08000000` and use Program & Verify. Do not erase the full chip unless you have an approved backup and recovery procedure.

## Update with STM32CubeProgrammer

Prepare ST-LINK, STM32CubeProgrammer, a stable 5 V control supply, and the selected release image.

1. Power the board control section from a stable 5 V source.
2. Connect ST-LINK to the first MCU SWD connector.
3. Select `ST-LINK` in STM32CubeProgrammer and connect.
4. Select the `*_release.bin` in the chosen release directory and set the start address to `0x08000000`.
5. Run Program & Verify directly; do not perform a full-chip erase first.
6. Connect ST-LINK to the second MCU SWD connector and repeat steps 3 to 5.
7. Power-cycle the board.

## Check the Board After Updating

Open the USB serial port for each MCU and send:

```text
AT+VER
```

Use a `CRLF` line ending. The response must match the programmed release; for example, G473 V66 returns:

```text
V66
```

Then query the saved settings:

```text
AT+SETFDCAN?
AT+SETRS485?
AT+SPIMODE?
AT+RS485RAWCH?
AT+BATAUTO?
```

Updates normally retain communication settings. If communication defaults must be restored, confirm that `AT+CFGERASE` is supported by the installed firmware before sending it.

## Factory Communication Defaults

| Item | Default |
| --- | --- |
| Classic CAN / CAN FD arbitration phase | 1 Mbit/s |
| CAN FD data phase | 5 Mbit/s with BRS enabled |
| RS485 | 4 Mbit/s, one stop bit, no parity, eight data bits |
| SPI | `SHORT`, 23 bytes per transfer |

For CAN FD through SPI, send:

```text
AT+SPIMODE=LONG
```