Set Arrows 301F to automatically accept RSA keys?
Likely you started the ADB the first time as ROOT, and now the device doesn't have the permission to write on $HOME/.android/adbkey
now you have to change the owner of that file (and everything else in that directory)
$ sudo chown &lt;your_username&gt; .android/&#42;   
 and eventually: 
$ chmod 777 .android/&#42;