I recently updated the firmware to version 5.20.346 since it prompted there's an update available.
This made my device slower, it froze when opening bigger books (it didn't do this before), and it didn't open certain DRM-protected books anymore (these opened just fine before the update).
I downloaded the old firmware (v.5.14.1225) so that I could downgrade back. However, now the updating process freezes to about 1/4 of the way.
Any suggestions on what to do?