this is the steps with all details
1- First things we need to install the cab file from the link below cab name MoviPatch_Eng_100416.cab in the rar file with name windows-1256__my storage back.
2- Free File Hosting Made Simple - MediaFire
3- After you install it in your mobile go to your ( File manager >>Temb >> MoviPatch >>NormalPatchUpdate.exe )
4- Switch your mobile off and take you battery out.
5- Return your battery to your mobile again and switch it on again
6- You will get massage have to chooses with strange language I think may be Chinese language OK whatever Chose the left on
7- Now go and chose as following (start >> settings >> general Settings >> USB Connection >> Mass storage)
8- Now connect you mobile O2 (GT-I800) to you PC it will directly identify your mass storage and ask for format it accept and format it
9- Now it will show in your PC it's available
Note: this only effect in storage part only and eras the file that was in the storage part only, So all the file in this part will delete >_> but at lest it will back
Some people they said after the 3rd step them Storage back with the information .. So maybe you can Stop in the 3rd Step otherwise you have complete the steps for my I didn't get it until complete the full steps
Congratulations your Storage back again … I hope it will help …
Just for your information My Storage is 16 GB and it's shown before 0 Mb and after applying those Step its back again
I wish you success and good luck all