thank you very much for all the answers

I still need some clarifications...please

I have tried to find out more information about rest file, but I’m not sure about what does it means!

Can you please give me some answers??
- is the rest file a generic mainfirmware of k750i?
- do only I have to reflash K750_R1DB001_MAIN_EU_1_CL_RED49.rar to bring back alive my cell?
- do you think I should repair the EROM (I have found this nice discussion Upgrading or repairing the EROM (FOTA) in phones CID 49 or CID 51 with Phone XS - Top Sony Forums )

Thank you so much