Error Fortigate Cannot booting no default firmware

[tronton_team]

Hello, i want to ask, my fortigate cannot boot, when i check in with CLI i discovered error like this

Booting OS...

No default firmware. You may try backup.

can anyone help me? i put error screenshoot

[sw2090]

Looks like there is no default firmware image on your Fortigate.

You could try to enter Bootloader (Press any key when told during bootup) and try to boot the backup image.

Otherwise you would have to use bootloader tftp to up a new firmware.