ZuluSCSI™ is a SCSI computer storage emulation platform, which speaks both SCSI-1 and SCSI-2. It uses file-based SCSI HDD & CD-ROM images, similar to RaSCSI and BlueSCSI. It represents a fusion of firmware and concepts from both SCSI2SD V6 and BlueSCSI. Hard drive and CD-ROM drive images are stored on a standard FAT32 or exFAT-formatted SD card.


  • Open-source firmware, licensed under the GPLv3
  • Emulates up to 7 SCSI devices simultaneously, including CD-ROM, Magneto Optical, removable (SyQuest/Jaz-style), and SCSI floppy device types
  • Speaks both SCSI-1 and SCSI-2, including 10MB/sec Fast SCSI
  • Up to 9.5 megabytes/second read speeds, 6MB/sec write speeds (on ZuluSCSI RP2040-based models)
  • SCSI Termination is DIP-switch controlled
  • Firmware upgrade simplicity; As easy as placing a file on the SD card
  • Highly configurable using a text-based ini file, ZuluSCSI.ini
  • External activity LED pin header for attaching remote activity LED
  • Designed to be powered via SCSI termination power, when provided by the host
  • Optional DB25 pin header for direct installation of an external SCSI connector, in addition to the Single-Ended 50 pin IDC connector
  • Identical dimensions and mounting holes as that of SCSI2SD V5.1, V5.2, and V6, making it compatible with many existing SCSI2SD-specific mounting solutions
  • SCSI bus transceivers, as used in SCSI2SD V5 and SCSI2SD V6 Rev F

Firmware structure

  • SCSI command implementations are from SCSI2SD
  • SCSI physical layer code is mostly custom, with some inspiration from BlueSCSI
  • Image file access is derived from BlueSCSI

Major improvements from BlueSCSI and SCSI2SD

  • Separation of platform-specific functionality to separate directory to ease porting
  • Ported to the RP2040 and GigaDevice GD32F205 ARM Cortex processors
  • Removal of Arduino core dependency
  • Simultaneous transfer between SD card and SCSI bus for improved performance

Origins and License

Firmware origins

The ZuluSCSI™ firmware is derived from two sources, both under GPL 3 license:


The ZuluSCSI™ RP2040, V1.0 and V1.1 hardware designs are derived from the SCSI2SD V5.1 hardware design. The ZuluSCSI™ RP2040 Mini hardware designs are derived from the SCSI2SD V5.5 hardware design.