Upgrading the FortiDB3KD from 5.1.7 to 5.1.13

First am asking ,  did the FortiDB 3KD Hardware plat form using the image with extension   .out ??   or .img ??

Am trying to upgrade my FortiDB ( 5.1.7-0017 ) to (5.1.13 -0033) 

The image 5.1.13 with extension .img was uploaded using the GUI , then the FortiDB became inaccessible  (though the GUI and SSH and )  it didnt work. 

i forgot to  upload  the resizing image first .    what should i do now??? 

Note:

i tried to access the FortiDB using the console in order to upload my old Firemware i used before ( 5.1.7 ) using the TFTP server . but fails to boot .

i choose [ B] Boot with backup firmware and set as default 

also i choose Get firmware image from TFTP server