Being able to connect to the system console of LinkIt Smart 7688 by using a serial (or UART) to USB cable is an absolute must. The Seeed Wiki puts the serial connection at the top of the getting started section but doesn’t explain how important it is. It is essential. As is understanding LuCI and the OpenWRT failsafe mode.
Updating to the 0.9.4 firmware via the web UI (section 4.6.1 in the manual) failed for me yesterday (unknown error) and left my board in a state where it failed to boot. It’s taken me hours to recover.
The factory reset using the Wi-Fi Reset button (section 4.6.4 in the manual) had no effect and I couldn’t get normal console access using either SSH or the system console, similar to this issue.
If this happens to you, I was able to trigger OpenWRT’s failsafe mode using the serial connection (section 220.127.116.11 in the manual), watching for the failsafe message during boot, then pressing the “f” key on the keyboard.
Once in failsafe mode, you have two special commands available:
firstboot reset settings to factory defaults mount_root mount root-partition with config files
Run mount_root first before trying anything else.
firstboot failed for me, it requires a yes/no input and defaults to no. No matter what I tried, I couldn’t stop it defaulting to no and quitting.
mtd -r erase rootfs_data is the alternative which worked for me. It reboots the board as part of the process. After that, I was able to access the board normally again via Web UI, SSH and the system console.
Make changes through the LuCI web interface or the UCI not the web UI. LuCI can be accessed by clicking the OpenWRT link at the top of the mylinkit.local web UI page.