i also have gotten used to it, but would like it fixed even if i decide not to use it inverted in future.
bookeen support responded today & gave me instructions and two file download links to enable me to reflash the firmware and re-update it to 2.1. they suggested that should fix it. that flash went OK.
had to re-set language, inertial sensor, file display & sort order etc. after.
side keys function exactly as before, that is : broken. the setting does not retain after a power off even tho the check stays next to the 'invert keys' item & i have to un-set it and re-set it to invert, then again power off/on loses it.
i shall persevere as a matter of principal, tho i shall not hold my breath waiting.
at least now i have a factory fresh system. i have passed this info on to them again.
best regards & i'll likely post something here after waiting the next 4 months
-wayne