If recovery codes fail, you must directly interface with the BIOS chip. This is typical for models like the or 5420 . How to Reset, Remove, or Recover BIOS Passwords | Dell US

On older Dell Latitudes (D-series, E6400), there was a dedicated 2-pin jumper labeled PSWD or Password . Shorting it would clear the BIOS password on boot. (Latitude 5480, 5490, 5590, 7xxx series), there is no PSWD jumper . Dell removed physical password jumpers around 2014. Instead, they use a crypto-processor.