So far...
Keyboard issues were fixed, and overall input speed were improoved. Code were rewrited and now it's stable, and useable

Now working on app's design, additional features and integration with current eDGe's eink software.
Still looking for way to improove power saving (my goal is to improove battery run time up to 7 days). Unfortunetally seems that all known ways were not enabled in kernel modules loaded in EE.