Unbricking
If your device's firmware got into a bad state (won't POST), you can try unbricking it.
TIP
Try performing a EC reset beforehand to see if your device can recover.
Here is the following ways that you can unbrick your device:
Unbricking with a ch341a USB programmer
Unbricking with a Suzy-Q cable
Unbricking with a flipper Zero
Adapted from https://wiki.mrchromebox.tech/Unbricking