Factory Authentication Recovery

This guide addresses factory firmware failures caused by accidentally erasing factory authentication information with Full chip erase, Mass erase, or an equivalent full-chip erase operation. Custom firmware does not depend on this authentication information and is unaffected.

The board contains two STM32F407 MCUs, identified in this guide by the PCB labels STM32(1) and STM32(2). A single USB Type-C connection links both MCUs through the onboard USB HUB, so COM port numbers, names, and Device Manager order do not identify the MCU number.

This procedure first programs UID Reader only onto the MCU labeled STM32(1). The only MCU returning UID Reader information is therefore STM32(1). UID Reader is then programmed onto STM32(2), and the new UID that differs from the first one identifies STM32(2). These two labeled UIDs must be used throughout recovery and verification.

Important: Do not use Full chip erase, Mass erase, any equivalent full-chip erase operation, or modify Option Bytes at any point in this procedure.

Downloads

Software or file

Purpose

Download

UID Reader V3 HEX

Read the hardware UID and inspect Sector 7 status

Download sanpo_v4_uid_reader.hex

UID Reader checksums

Verify the UID Reader BIN/HEX files

Download SHA256SUMS.txt

UartAssist

Windows serial terminal

Download UartAssist.zip

STM32CubeProgrammer

Program and verify firmware through ST-LINK

Download STM32CubeProgrammer_win64.zip

Spine V4 V47 factory firmware

Program after authentication is restored and verified

Download spine_v4_v47_release.bin

The STM32_1_<UID>_sector7.hex and STM32_2_<UID>_sector7.hex files returned by customer service contain device-specific authentication information. They cannot be downloaded from the public repository and must not be replaced with files for another board.

1. Prepare the Tools

  1. Download and extract UartAssist.zip, then run UartAssist 5.0.2.exe. Installation is not required.

  2. Download, extract, and open STM32CubeProgrammer.

  3. Download sanpo_v4_uid_reader.hex.

  4. Prepare an ST-LINK and a USB data cable, and locate the STM32(1) and STM32(2) labels on the PCB.

  5. Connect ST-LINK only to the MCU currently being operated on. Keep USB Type-C connected.

2. Read and Label the Hardware Information of Both MCUs

2.1 Read STM32(1) First

  1. Following the PCB label, connect ST-LINK to the SWD connector for STM32(1) and power the board.

  2. In the upper-right corner of STM32CubeProgrammer, select ST-LINK and use:

    • Port: SWD

    • Frequency: keep the default; reduce it if the connection is unstable

    • Reset mode: start with the default; use Under Reset if connection fails

  3. Click Connect and confirm that the log identifies an STM32F407.

  4. Open Erasing & Programming and select sanpo_v4_uid_reader.hex. The HEX file already contains address 0x08000000; do not enter an address manually.

  5. Select Verify programming and click Start Programming. After success, click Disconnect, then power-cycle or reset the board.

  6. Wait for USB HUB enumeration. One COM port may appear, or two may appear if the other MCU’s existing firmware still runs. In UartAssist, check every currently available COM port using:

    • Baud rate: 115200

    • Data bits: 8

    • Stop bits: 1

    • Parity: None

    • Flow control: None

    • Send and receive mode: text/ASCII, not HEX

    • Line ending: CRLF UartAssist serial settings

  7. Send AT+HWINFO to each port. Do not type the literal characters \r\n. At this point, only STM32(1), which is running UID Reader, returns a line in this format:

SANPO_V4_HWINFO,V=3,UID=XXXXXXXX-XXXXXXXX-XXXXXXXX,SECUID=FFFFFFFF-FFFFFFFF-FFFFFFFF,DEVID=413,REVID=XXXX,FLASHKB=512,SECTOR7=BLANK

  1. Copy the complete line and label it clearly as STM32(1). Do not save or rely on the current COM number, because its number and order may change after reconnecting or resetting the board.

If no port returns SANPO_V4_HWINFO,V=3, or two different V3 responses appear, stop the procedure. Check the programming target and log, then contact customer service.

2.2 Read STM32(2)

  1. Move ST-LINK to the SWD connector identified by the STM32(2) PCB label.

  2. Program and verify sanpo_v4_uid_reader.hex in the same way as for STM32(1), then power-cycle or reset the board.

  3. Use UartAssist to open every COM port enumerated by the USB HUB and send AT+HWINFO.

  4. You should now obtain two different SANPO_V4_HWINFO,V=3 lines:

    • The line whose UID matches the first saved value is STM32(1).

    • The new UID, which differs from the first value, is STM32(2).

  5. Copy the complete new line and label it clearly as STM32(2).

If you do not obtain two different UIDs, do not guess the relationship between an MCU and a COM port. Recheck the second programming operation and all COM ports.

2.3 Send the Information to Customer Service

Send both complete original lines and retain the following labels:

STM32(1): SANPO_V4_HWINFO,V=3,UID=........-........-........,SECUID=........-........-........,DEVID=413,REVID=....,FLASHKB=512,SECTOR7=....
STM32(2): SANPO_V4_HWINFO,V=3,UID=........-........-........,SECUID=........-........-........,DEVID=413,REVID=....,FLASHKB=512,SECTOR7=....

3. Check the Recovery Package from Customer Service

The recovery directory should contain:

  • STM32_1_<UID>_sector7.hex: only for the MCU identified by the STM32(1) PCB label

  • STM32_2_<UID>_sector7.hex: only for the MCU identified by the STM32(2) PCB label

  • spine_v4_official.bin

  • manifest.json

  • SHA256SUMS.txt

  • Customer recovery instructions

Both Sector 7 filenames contain the MCU position label and that MCU’s hardware UID. Before programming, confirm that the UID in each filename exactly matches the corresponding UID saved in Section 2. Never exchange the two files.

UID Reader status fields mean:

  • UID: the current MCU’s actual hardware UID.

  • SECUID: the UID stored in Sector 7; an empty area normally contains all F characters.

  • BLANK: the Sector 7 authentication block is empty.

  • INVALID: the Sector 7 format, length, end marker, or CRC is invalid.

  • UID_MISMATCH: SECUID differs from the current MCU’s actual UID, which means the device-specific HEX file was programmed onto the wrong MCU.

  • UID_MATCH: SECUID matches the actual UID, and the format and CRC are valid.

4. Restore and Verify STM32(1)

  1. Following the PCB label, connect ST-LINK to the SWD connector for STM32(1).

  2. Connect in STM32CubeProgrammer, open Erasing & Programming, and select STM32_1_<UID>_sector7.hex. The HEX file already contains address 0x08070000; do not change the address.

  3. Select Verify programming and click Start Programming. After success, disconnect and power-cycle or reset the board. UID Reader is still running at this point.

  4. Use UartAssist to query every currently enumerated COM port. Identify the STM32(1) response by the hardware UID saved in Section 2, not by the COM number.

  5. All three conditions must be met:

    • UID exactly matches the previously labeled STM32(1) UID.

    • SECUID exactly matches UID.

    • SECTOR7=UID_MATCH.

  6. Only after verification, reconnect STM32CubeProgrammer, select spine_v4_official.bin from the recovery package, manually enter download address 0x08000000, keep Verify programming selected, and start programming.

If UID_MISMATCH, INVALID, or an incorrect UID appears, do not continue with factory firmware. Save the UID Reader response and STM32CubeProgrammer log and contact customer service. Do not perform a full-chip erase.

5. Restore and Verify STM32(2)

  1. Following the PCB label, move ST-LINK to the SWD connector for STM32(2).

  2. Select STM32_2_<UID>_sector7.hex, then program and verify it in the same way as for STM32(1).

  3. Before factory firmware overwrites UID Reader, query every currently enumerated COM port again. Identify the STM32(2) response by the saved hardware UID and confirm UID=SECUID and SECTOR7=UID_MATCH.

  4. Only after confirmation, program spine_v4_official.bin from the recovery package at 0x08000000.

6. Final Verification

  1. After both MCUs are complete, disconnect board power for 10 seconds and then power it again.

  2. In UartAssist, open both COM ports enumerated by the USB HUB and send AT+VER in text mode with a CRLF line ending. Confirm that both ports return the factory firmware version.

  3. Test CAN, RS485, SPI, and motor communication as required by the application.

AT+VER only confirms that the factory firmware is running. By itself, it does not prove that a Sector 7 file was programmed onto the correct MCU. Before programming the factory firmware, the UID Reader response must confirm UID=SECUID and SECTOR7=UID_MATCH.

If programming fails, a status is abnormal, or the factory firmware does not respond, stop the procedure. Save both labeled, complete SANPO_V4_HWINFO lines and the STM32CubeProgrammer log, then contact customer service.