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Twinkie / Twonkie firmware sources

These sources are the original sources from the Chromium OS Embedded Controller project, stripped down to the minimum required to build the Twinkie/Twonkie firmware.

Building

Prerequisites

Beyond what your distro should provide anyway, you'll need arm-none-eabi-gcc to build the firmware and not much else.

Building the Twonkie firmware

  • make -j BOARD=twonkie for Twonkie v1 hardware
  • make -j BOARD=twonkiev2 for Twonkie v2 hardware
  • make -j BOARD=twinkie for the original Twinkie

The completed firmware will end up in build/<BOARD>/ec.bin and can be flashed as is.

Or you can run buildall.sh to build all three images.

Pre-built firmware

Check out the GitHub Releases page for pre-built firmware images.

Flashing

For flashing you'll need dfu-util. On Linux your package manager should offer a package for it, for Windows you can find builds on their SourceForge site.

Enter the bootloader

There are several ways to put Twinkie or Twonkie into bootloader mode:

  1. Twonkie only: Via the bootloader button. Press and hold the button while plugging in the USB cable.
  2. Via a cursed OTG cable. Plug an A-to-A USB cable into an USB-OTG adapter and use that concoction to connect Twonkie to your computer. The OTG adapter pulls the ID pin on the Micro-B connector high, a circuit on the Twonkie board detects this and asserts the STM32's bootloader signal.
  3. Via the dfu command at the USB console. Obviously this only works once there's a working firmware on the chip.

Flash the firmware

dfu-util -a 0 -s 0x08000000 -D ec.bin

Exit the bootloader

If you entered DFU mode via the button or a cursed cable, just unplug Twonkie and plug it in again using a regular cable.

If you entered DFU mode via the dfu command at the console, you have to switch back using this command:

dfu-util -a 0 -s 0x08000000:force:unprotect

This will not actually flash anything, it will only exit the bootloader.

USB console

Linux

Twonkie has a simple console mode using a pair of bulk USB endpoints. In Linux, the USB serial driver should support this mode and make the console available as /dev/ttyUSBx. If that device doesn't show up immediately you can try

sudo modprobe usbserial
echo '18d1 500A' | sudo tee /sys/bus/usb-serial/drivers/generic/new_id

Windows

For Windows there's a simple USB console program in util/shell.py. It requires the libusb1 package from PyPI.