GD-Rom SD Card Dumping Guide
From Redump Wiki
Ideally you'll dump with the GD-Rom Dumping Guide, however some GD-Roms will NOT work with that method and require dumping the HD area with an SD Card.
- Dreamcast console
- SD Card
- SD Card / Dreamcast Adapter 
- SD Rip 1.1 (burn this to a CD-R with DiscJuggler)
Dumping Retail / Pressed GD-Roms
Dreamcast SD Rip is a program that can be used to dump Dreamcast games, including GD-R prototypes.
- Connect the SD adapter.
- Boot the Dreamcast SD Rip disc.
- Swap in the disc you want to dump.
- Select GD-ROM <bin> all track.
- Need a System Disc 2. This will unlock GD-R dumping.
If the HD area has only one track, please submit along with a Plextor dump of the LD area. If the HD area has more than one track, the tracks will need to be properly split to conform to Redump standards (Fireball knows hows to do this).