Disabling write protect with a SuzyQable

TIP

This method is only available on CR50 devices.

TIP

This method requires a SuzyQable, a chromeOS debug cable.


Step 1: Enabling Closed Case Debugging (CCD)

  1. Open VT-2 (ctrl + alt + f2 (right arrow)).
  2. Login as root.
  3. Run gsctool -a -o.
  4. You will be prompted to press the PP (physical presence) button several times. This is a fancy way of saying to press the power button. This process takes several minutes and ends with the message PP Done!.
  5. The device will suddenly reboot and exit developer mode. Re-enable developer mode and continue with the instructions.

Step 2: Disable Write Protect.

  1. Open VT-2 (ctrl + alt + f2 (right arrow)).
  2. Login as root.
  3. Plug in your cable
  4. Run ls /dev/ttyUSB* to verify your cable is working. This should output 3 items, ttyUSB0, ttyUSB1, and ttyUSB2. If you do not see these items, try flipping the usb-c end upside-down, and try another usb-c port. If there is still no result, confirm your cable was assembled properly.
  5. Run the following commands. This will disable hardware write protect.
  • echo "wp false" > /dev/ttyUSB0
  • echo "wp false atboot" > /dev/ttyUSB0
  1. Run echo "ccd reset factory" > /dev/ttyUSB0 to be able to unbrick using a suzyqable, if needed.
  2. Run gsctool -a -I to verify you have opened all the CCD flags. The current value for all CCD flags should be set to Y/Always.
  3. Verify crossystem wpsw_cur returns 0.
  4. Reboot.
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