At the end I managed to update all BIOS of my machines by using the manifacturer original zip file.
Once extracted there are various files, fun part they changed the name of the main executable that had to be run via EFI with a less obviousy one and also added a FLASH.NSH file where .NSH are the EFI equivalents of .BAT in Windows and .SH in Linux.
So here's the procedure: unzip the ZIP content and put it in a flash drive, at the startup go in BIOS settings and select "Boot EFI shell", when the boot is complete go inside the flash drive content with cd fd0 or similar command where fd0 is your flash drive. At this point I first used the utility provided to do a backup copy of the current BIOS and then ran the FLASH.NSH file, then reboot and remove the external flash drive.
Answer from user3450548 on Stack Exchange