Who this is for
Toyota or Lexus owners with a C-SDSU who need newer firmware and are handy with wires.
FrogPilotHardware and wiringAdvanced
Flash new firmware onto a Toyota smart DSU
Splice two USB cables into a programming lead, then load the firmware with STM32CubeProgrammer 2.14.0.
You need
- Two USB cables that carry data, plus tape or heat shrink
- Your smart DSU module
- STM32CubeProgrammer 2.14.0 and the TinyBear firmware file
In plain words
Why this guide matters
A smart DSU lets openpilot control speed and braking on some Toyota and Lexus cars. Newer firmware sometimes needs to go onto the module, and this guide shows how with a home-made cable. It is unofficial, fiddly and only for the C-SDSU, so read the warnings first.
The short version
What the full guide walks you through
Cut and join the two cables into one programming lead.
Connect the lead to the module and the computer.
Open the programmer, connect, and load the firmware file.
Refit the module and test in the car.
Before you start
- Does not apply to Erich's SDSU design.
- A wrong splice can damage the module; ask TinyBear before starting.
The full wiki page belongs to FrogPilot. Checked on September 10, 2026. Their last update was October 7, 2024.
Quick answers
Questions people ask
Which smart DSU does this cover?
The C-SDSU with TinyBear firmware. It does not apply to Erich's SDSU design; ask him for that one.
What software do I need?
STM32CubeProgrammer version 2.14.0, which is free, plus the firmware files from TinyBear's GitHub page.
Can I damage the module?
Yes; a wrong splice or grounding mistake can. The author suggests asking TinyBear before starting.
Check your car
Cars this guide talks about
Support changes by year and trim. Open your exact car before you buy anything.
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Check your exact car first, then choose software and hardware.
Photos: comma.ai. Guide content belongs to FrogPilot. CommaGuide is an independent guide and is not affiliated with comma.ai or FrogPilot.
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