The A20-OLinuXino-Lime2 can’t be bricked, as far as I know. You can always remove the SD card and a insert a fresh one with latest Pioneer image and it will come back fresh from any state.
But first thing to try is to reboot the machine. However, simply removing the power plug and re-inserting will not work. Since the Pioneer has a battery, you will need to unplug the battery or use the power button to reboot properly.
If that does not work, insert the SD card into a PC and examine the logs in /var/log/syslog file. It is likely that you have btrfs snapshots of the earlier working state (automatically taken hourly, daily, monthly etc. and not each package install), set the filesystem to boot from an older snapshot. Insert back the SD card and boot. (will give you details instructions if necessary).
In the unlikely worst case, prepare a fresh SD card with Pioneer image and manually restore the data from the old one.