LG G5 boot into recovery show-stopper (maybe not understanding the manual)

OK, I was not able to do so. I describe the steps:

  1. Being in Bootloader mode, just after flashing TWRP
  2. adb reboot recovery is not working (no devices/emulators found) – I understand that the phone is not prepared to receive adb command
  3. Volume Down + Power (nothing would happen holding them down for 20 so seconds)
  4. bootloader reboot sends the phone in reboot. (still holding buttons)
  5. LG logo appears
  6. release the Power button for a second (still holding Volume Down)
  7. push the Power button again
  8. “Factory data reset” appears [No(Exit)/Yes] (been here and done that, Android would be restored)

I did not get any other Recovery menu (with Backup, Wipe,…)