I have a student who is working on real-time tracking of our University's loop-bus, together with displays at each bus stop to tell how many minutes until the loop-bus next arrives.
We are using Kindle paperwhite e-readers as the e-ink display will be easy to read during the day, and it includes a backlight to allow for night-time visibility.
The Kindles are fairly easy to root and modify, however, as with all these sorts of things, it is possible to mess things up so that it won't boot, i.e., bricking it.
We did indeed manage to brick our Kindle, and set off on a protracted adventure to work out how to unbrick it. We were greatly frustrated by the lack of a clear and authoritative set of instructions on how to do this, and thus decided to fix this by documenting the process.
Tobias has summarised the method in the following gist:
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