Starling 2 / VOXL2 M0129 ESC not detected during voxl-esc scan or firmware upgrade

[syamala kotireddy]

Hi ModalAI team,

I am working on a Starling 2 / VOXL2 setup and I am stuck with an ESC communication / firmware issue. I would appreciate your guidance on whether this looks like a software mismatch, a known M0129 compatibility issue, or a hardware-side comms problem.

Hardware / platform:

• VOXL2 (M0054)
• Starling 2 platform
• ESC board label: M0129
• SKU shown on device:
  MRB-D0014-4-V1-C27-T9-M22-X0

Current software versions:

• system-image: 1.8.06-M0054-14.1a-perf
• voxl-suite: 1.6.3
• voxl-esc package manually upgraded from 1.5.7 to 1.6.1

What I did:

1. Reflashed the board
2. Restored / checked calibration as needed
3. Verified Wi-Fi and internet access
4. Confirmed newer voxl-esc was available in sdk-1.6 and manually installed:
   dpkg -i /data/voxl-esc_1.6.1_arm64.deb
5. Checked available firmware files under:
   /usr/share/modalai/voxl-esc-tools/firmware/

Firmware files present for M0129:

• modalai_esc_firmware_m0129_3_v39_25_a58f5f6f.bin
• modalai_esc_firmware_m0129_6_v39_25_a58f5f6f.bin

Note:

• My physical ESC only says M0129
• I do not see a suffix like M0129-3 or M0129-6 printed on the board
• I also do not see an m0129_1 firmware file in the installed firmware folder

Main issue:

• voxl-esc scan does not reliably detect any ESCs
• voxl-esc upgrade_firmware sometimes previously said “successfully pinged ESCs” but then failed with:
  [ERROR] Unknown board detected:
• After deeper testing, the underlying Python tools also fail to detect the ESC consistently

Direct tool results:

1. voxl-esc-scan.py

• No ESCs detected at all baud rates
• Sometimes reports:
  ERROR: voxl_uart_read_bytes: Bus '12' is not initialized

2. voxl-esc-board-detect.py

• Ends with:
  ERROR: No ESC(s) detected, exiting.

3. Debug scan:
   Command used:
   python3 voxl-esc-scan.py --enable-debug True --force-scan-all-baud-rates True

Observed behavior:

• UART TX packets are clearly being sent
• No valid UART RX from ESC
• In one case RX was all zeros after:
  ERROR: voxl_uart_read_bytes: Bus '12' is not initialized
• Every scan ends with:
  WARNING: No ESC(s) detected
  ERROR: not all ESCs found

Relevant logs:

• dmesg shows SLPI restart events after reset commands, for example:
  Fatal error on slpi!
  ... Got kill command from apps processor.
• /dev shows SLPI subsystem nodes, but the scan path still fails to get a valid ESC reply

Important observations:

• The VOXL side appears to be transmitting on the ESC link
• The ESC side does not appear to respond
• This now looks more like a low-level comms / wiring / power / bootloader issue than just a wrapper-script issue

Questions:

1. Is system-image 1.8.06 with voxl-suite 1.6.3 a supported combination for Starling 2 + M0129 ESC?
2. For an ESC labeled only “M0129”, which firmware should be used:
   • m0129_3
   • m0129_6
   • or is there another variant / package expected?
3. Is the missing response from the ESC more indicative of:
   • incorrect harness / connector / pinout
   • ESC not powered correctly
   • damaged ESC MCU
   • wrong firmware / bootloader state
4. Is there a recommended low-level recovery path for M0129 when voxl-esc-scan.py cannot detect any ESCs?
5. Are there any additional commands you want me to run to verify the ESC UART / SLPI bridge path on this platform?

Example command outputs:

system image / suite:

• system-image: 1.8.06-M0054-14.1a-perf
• voxl-suite: 1.6.3

voxl-esc version after manual install:

• 1.6.1

Direct scan result:

• WARNING: No ESC(s) detected
• ERROR: not all ESCs found

Direct board detect result:

• ERROR: No ESC(s) detected, exiting.

Any help would be greatly appreciated. I can also provide full logs or photos of the ESC board/harness if needed.

Thank you.

[Alex Kushleyev]

@syamala-kotireddy ,

If your M0129 ESC only has a label that says M0129, it most likely means it is M012-3. The only difference between -3 and -6 is that -6 is rated for 6S battery voltage (which is irrelevant for Starling 2).

Was the ESC working? How did it get into non-working state?

Please make sure PX4 is not running before you use the voxl-esc tools : systemctl stop voxl-px4. You should reboot, disable voxl-px4 and try to use voxl-esc tools directly from /usr/share/modalai/voxl-esc/

In order to test if the ESC itself is working, the best way to connect it directly to a Linux PC using a serial-to-usb adapter and use voxl-esc to scan, test, etc. You can make your own adapter or purchase one here.

Also, double check if the status of ESC LEDs when you turn on the power. Additionally, does the ESC make motor sounds? See additional debugging information here : https://docs.modalai.com/voxl-escs/faq/

Alex