Alberto, from your last post the apk download seems still to be corrupted?
Hi Mog, I am very surprise to hear that! I did downloaded the zipped folder system and the apk and have re-installed everything as a new installation (erased the folder system from the root and removed the apk installation) Got a working speadsheet again.
If the installed the APK only shows a dark blue screen, it means you don't have the SSheet folder system correctly installed.
Please note that the SSheet folder contains 7 sub-folders named as follow: (See attached pictures)
Data (contains 1 text file)
Manuale (contains 1 pdf file)
Sounds (contains 3 wav files + 1 wma file)
This system folder (SSheet) must be copied in the root of your smartphone before your launch the apk. (once copied, please open it it should show the same sub-folders as the attached picture and check if each of them contains the files reported above)
Please follow the above instruction and let me know if you have got it working. I am sorry but I am unable to put together an auto-install apk! I tryed also the Emile's RFO2APK without any luck!