Unbricking Procedure for VOXL and VOXL Flight
Table of contents
Overview
The System Image flashing process requires the device to be in fastboot mode. The typical process uses adb to put the VOXL into fastboot mode over USB. If the device is bricked and one cannot get the VOXL into fastboot using USB, then you’d follow this process before running the install.sh script as described in the Flash System Image process.
The following VOXL add-on boards support the force fastboot mode switch:
- USB and Serial Debug Expander (datasheet)
Video Tutorial
Force VOXL into fastboot
To force the VOXL to boot into fastboot mode:
- Power off the VOXL
- Detach VOXL USB cable (to ensure USB is not supplying any power VOXL)
- Attach the USB Expander and Debug Add-On board
- Ensure the
FASTBOOTlabeled switch is set to on - Ensure the
EMERG BOOTlabeled switch is set to off- NOTE: if your board is missing the
EMERG BOOTswitch, this is OK as its default un-populated state is OFF
- NOTE: if your board is missing the
- Power on the VOXL
- Reattach VOXL USB cable
- After VOXL boots up (about 5 seconds), set the
FASTBOOTback to off
You can verify you are in FASTBOOT with the following command:
sudo fastboot devices
You should see an output like:
a0259b4a fastboot
Reflashing System Image after Forcing the VOXL into Fastboot
To reflash the System Image, run the following while in Fastboot mode:
$ sudo ./install.sh -f
Flashing the System Image using install.sh is covered in this section.
Prevent Flash Corruption (i.e., Bricking)
With flash, like what is used on VOXL, removing power while the kernel is writing will result in corruption and bricking of the board. It can happen during development when a lot of changes are being made on the board and then power is removed.
Use the /data partition for file storage to avoid this issue.
Linux has a setting for how often the flash is committed to reduce the risk, but of course there could be different side effects. You can see a writeup on the topic here, as it is common in all of this type of single board computers
Your smartphone fixes this by making you press the poweroff button before shutting off power.
To prevent flash data corruption, run poweroff before removing power:
$ poweroff -f