Flashed the r2zur35wd.iso available on the lenovo website but updating the UEFI / BIOS with it got an error.
I was able to update the UEFI / BIOS by mounting (in linux) the USB drive flashed with the ISO and copying the files in the FLASH directory to a dir in my /boot
then moving the FL1 file in the subdir one dir up to be in the same directory as the ShellFlash.efi, without doing that I got ERROR 081 - Failed to load BIOS image file! Status = 101
Then ShellFlash.efi -file filename.FL1 and it installed a EFI capsule and rebooted and succesfully updated the UEFI