Ignore this I figured it out
Sorry, but the operation only worked on one device (single sim). With the other (same model of smartphone but dual sim), once the procedure is completed, the error "Your Device Has Failed Verification And May Not Work Properly" appears. The phone gets stuck on that screen! If I repeat the procedure by checking the item "Disable FBLOCK" it works but the bootloader remains unlocked. I also tried flashing the bootloader for Kirin659 (A) and Kirin659 (B) but nothing.