Originally Posted by xorphex
I can, however, connect with username 'framework' and password 'mario', but without root-privileges...
I recommend logging in as framework:mario and saving the contents of /etc/shadow to a file on a host pc (using copy/paste) and using john the ripper to crack the root password. If it is a fionaXXX or fionaXXXX password, you can do that instantly with the wordlist provided in another thread.
You might try removing the last hex digit from your fionaXXXX password. On all of my kindles DX, DXG, and 3 different K3's, all of them used 3 hex digits.
UPDATE: all passwords are 8 characters or less, such as fionaXXX (3 hex digits). Extra characters are ignored.