RolandSamplers
16-pad sampler with onboard effects and pattern sequencer
The SP-404MKII is a compact sampler from Roland, released in 2021 as the successor to the SP-404 line. It has 16 velocity-sensitive RGB pads plus a sub pad, 32-voice polyphony, 16 GB of internal storage and a graphic OLED display. The unit includes a large set of bus effects, a pattern sequencer with real-time and step recording, a mic and guitar input, MIDI in and out, and USB-C audio. It can run from mains power, USB, or AA batteries.
Both entries here are layers on top of Roland's own system rather than replacements for it. DOOM OS is built by patching the official 5.52 update file in your browser, and running the updater with Roland's original file restores stock.
Heavily modified 5.52 firmware that adds a graphical pattern sequencer, piano roll, live recording, mixer, effect automation and undo in a "shadow OS" opened with REMAIN + SUB PAD.
by Quintus Oostendorp (Klangfeld Labs)
| Version | Date |
|---|---|
| 0.6.2-alpha (build 3824) | 2026-10-06 |
| 0.6.1-alpha | 2026-10-04 |
| 0.6-alpha | 2026-09-29 |
Screen-reader firmware for the SP-404MKII based on system program 5.52. A speech engine reads screen titles, menu items, values, sample names and pad steps aloud so a blind musician can use the display-driven functions.
by Mudb0y
| Version | Date | Notes |
|---|---|---|
| 2026.10.06 | 2026-10-06 | New speech engine that reads file lists, the pattern screen and recording settings; firmware unchanged. |
| 2026.09.29 | 2026-09-29 | New speech engine that reads many more screens; firmware unchanged. |
| 2026.09.26 | 2026-09-26 | First release. |
Announced OS layer for the SP-404MKII with a ducker, per-bus filter, lo-fi and EQ, four LFOs and four Euclidean rhythm lanes. Not yet downloadable.
Windows emulator that runs Roland's own SP-404MKII system program 5.52 on an emulated i.MX RT1060 in a QEMU fork, with an on-screen panel, MIDI, TouchOSC control and a VST3 plugin for DAW tracks.