Hydro Thunder for Dreamcast non-working Easter Egg

[atari2600land]

Per the rarity guide:


Easter eggs: To unlock every boat and every track, start a new game and race one of the Beginner tracks. Enter the initials "?PB" in to the high score listing.

Wrong. I tried it. It didn't work.

[Nz17]

According to http://www.gamewinners.com/DC/HydroThunder.htm :


Hydro Thunder. All boats and tracks: Get one of the top five times in any track and enter ?DL as a name. Note: Enter ?PB as a name in the European version of the game.

[atari2600land]

?DL doesn't work either.