BBSHD firmware failure

[moutchz]

BBSHD still runs but no software/display can read or write controller anymore – possible UART/firmware corruption?

I’m trying to diagnose a weird BBSHD issue and I’m running out of ideas.

The motor still powers on and the bike runs normally, but I can no longer communicate with the controller through ANY software or display-based tuning method.

What happened:

• I was modifying settings on the BBSHD
• Afterward, communication with the controller stopped working
• Since then, no tool can properly read/write the controller

What I already tested:

• Multiple programming attempts
• Different software:
  • Bafang Config Tool
  • Speeed app
  • EggRider
  • other tuning/config apps
• Different USB ports/computers
• Tried disconnecting peripherals
• Bike still runs normally
• Display still powers on
• Motor still functions

Important details:

• EggRider also cannot read/write the controller
• Programming cable also cannot read/write the controller
• This makes me think it’s not just a display issue
• No permanent error codes on display
• Controller is responsive enough to operate the motor normally

Things I’m trying to determine:

1. Does this sound more like:
   • corrupted firmware/EEPROM
   • damaged UART communication section
   • partially bricked MCU
   • something else?
2. Is there an actual recoverable stock BBSHD firmware available anywhere?
   • not config files, actual firmware
3. Has anyone recovered a controller in this exact state using:
   • STC ISP
   • Daniel Nilsson firmware tools
   • bootloader recovery
   • UART reflashing?
4. If both EggRider and programming cable fail to communicate, does that strongly point toward hardware failure?

At this point I’m mainly trying to determine whether this controller is realistically recoverable or whether I’m wasting time chasing firmware files.

Any help from people who’ve actually recovered a “runs normally but unreadable” BBSHD would be hugely appreciated.

 

[Gionnirocket]

Have you tried a new 1T4 cable?
If so, might be easier to just replace the controller, about $150 USD
Flashing the firmware probably requires special tools that might not be end user available and more expensive if tracked down anyway.
Though I believe the Bafang BESST CANbus tool has UART communication capabilities.
And if ends up being a hardware issue, it still won't fix it.