Ok, the first step is to become familiar with both ADB and EDL. Can you get an ADB shell? You can find the EDL stuff in my sig, follow the instructions, make sure that you can get into EDL, load a loader, list the GPT and reboot with /z.
The update that you will be using is
http://firmware-us.boox.com/e275d1c3...cde/update.upx You will need to decrypt that with DeBooxUpx.py (Google it).