Ricoh GR custom firmware: GR Mod, LUT, XPan and every other mod, by camera
GR shooters have spent October 2026 taking the GR firmware apart. This page lists every public project we could find that patches, rebuilds or studies the firmware of a Ricoh GR: what each one changes, which bodies and firmware versions it names, whether anything goes onto the camera, and what its own author says went wrong. Read from GitHub on 19 Oct 2026; GRKit, which loads from the card and leaves the firmware alone, added on 24 Oct 2026.
中文版
None of this is made, checked or supported by Ricoh. A modified firmware file can freeze the camera, make it fail to start, or brick it for good, and a repair may not be covered by the warranty.
We have not flashed any of these projects onto our own cameras. We do not publish install steps, commands or download links here, only the project pages. Read the author’s own limits before you decide anything.
Every test result and safety claim on this page is the author’s own, taken from their README or release notes. We have not checked any of it. When a row says “tested”, it means the author says so.
We do not support or recommend any of these unofficial projects; they can break at any time. We list them as GR news, to show what the community is building. We have no ties to any project or author and get nothing from them.
Our read, as GR shooters
We shoot GRs, and we get the pull. Your own .cube look as an Image Control, a 65:24 frame, a date in the corner, twelve settings boxes: the GR does not do these out of the box, and Ricoh has not said it will.
The work is careful. Several authors publish test tables, keep the original firmware version and tell you how to go back. The same authors write that they tested on one camera, and that a camera that will not start may need a Ricoh repair.
Respect to the people who try these first and write down what broke. We are not going first. If you do, use only the firmware version the author names, read their trouble notes, and keep Ricoh’s own file for going back.
GR custom firmware by camera
GR IV
Official: Ricoh firmware 1.11 (13 Feb 2026).
- GR Mod (Ricoh-GRMod) (writes to camera): 1.11. Colour model; the Monochrome looks can be added.
- gr-custom-tool (writes to camera): GR4 firmware 1.11.10.x; feature writes on the verified official 1.11.10.7 layout.
- GR4-LUTSmith (writes to camera): 1.11, tested by the author.
- GR4-XPanUnlock (writes to camera): 1.11 only. Other models not supported.
- GR4-MonoUnlock (writes to camera): 1.11 only. Other models not supported.
- GR4-GF2Unlock (writes to camera): 1.11 only. Other models not supported.
- GR4-WebCam (writes to camera): 1.11. The README does not name the HDF or Monochrome.
- GR4-DOOM (writes to camera): 1.11, standard model. GR IV HDF not tested.
- ricoh-gr4-hlg-mod (writes to camera): 1.11, standard edition (the README names the mainland China version).
- GR-DLC (writes to camera): 1.11. Nine-slot build checked in software, waiting for a camera test.
- m10v (writes to camera): 1.11. Waiting for a camera test.
- GR Color Studio (writes to camera): Experimental in-camera colour-table backup, swap and restore.
- GR IV firmware analysis and feature expansion (writes to camera): Power-off picture workflow for the GR IV family.
- GRKit (writes to camera): 1.11 tested on a camera; 1.20 experimental, including the 30th Anniversary Edition’s factory 1.20. One package for both.
- QEMU Everything (research): 1.11, emulator only.
GR IV HDF
Official: Ricoh firmware 1.11, the same file as the GR IV.
- GR Mod (Ricoh-GRMod) (writes to camera): 1.11. The added slots were tried on a GR IV HDF as test firmwares 022 to 034.
- GR4-LUTSmith (writes to camera): 1.11. Version 2.2.0 tested on a GR IV HDF.
- GR-DLC (writes to camera): 1.11. Same as the GR IV.
- GRKit (writes to camera): 1.11 supported (same runtime, not tested itself); 1.20 experimental.
GR IV Monochrome
Official: Ricoh’s GR IV firmware page does not list it.
- GRKit (writes to camera): 1.00 supported and 1.10 experimental, without Image Control. Uses the GR IV package.
No firmware mod we read names the GR IV Monochrome as a body to install on. GR4-LUTSmith, GR4-MonoUnlock and GR4-XPanUnlock exclude it in so many words. GR Mod’s firmware knows the model, but its 0.7.0 notes say the added Image Control slots do not show on it. The one exception is GRKit, a card script that leaves the firmware alone: it names the Monochrome, without its film looks.
GR IIIx (incl. HDF, Urban Edition)
Official: Ricoh firmware 1.60 (23 Oct 2025).
GR III (incl. HDF, Street, Diary editions)
Official: Ricoh firmware 2.10 (23 Oct 2025).
GR II
Official: Ricoh firmware 3.00.
- m10v (nothing written on this body): 3.00. Inspection only; modified export not open.
- FRAME (FRAME-GR2) (writes to camera): Ricoh 3.00 first, then the FRAME firmware (WN3 default; WN9 in test).
- ricoh-gr2-boot-screen-mod (nothing written on this body): 3.00. Static analysis only; neither path tried on a camera.
- GRsync (no firmware change): Photo copy over Wi-Fi.
- RICOH GR Bluetooth API (no firmware change): Bluetooth reference.
GR (2013, APS-C)
Nothing found. We searched GitHub for GR firmware projects on 19 Oct 2026 and found no mod or patcher for the 2013 GR.
GR Digital I to IV
Nothing found. No public mod, patcher or firmware research project names a GR Digital body.
All projects compared
| Project | Cameras | What it changes | On the camera | Licence | Stars | Updated |
|---|
| GR Mod (Ricoh-GRMod) | GR IV, GR IV HDF, firmware 1.11 | Imported .xmp / .cube looks in up to six new slots, extra aspect ratios, ADJ soft focus, date imprint, power-off pictures, mono looks on colour bodies | Writes a modified firmware file | GPL-2.0 | 117 | 2026-10-17 |
|---|
| gr-custom-tool | GR IV, firmware 1.11.10.x | Crop ratios, power-off pictures, looks from .xmp profiles, a downgrade-friendly version option | Writes a modified firmware file | GPL-2.0 | 77 | 2026-10-17 |
|---|
| GR4-LUTSmith | GR IV, GR IV HDF, firmware 1.11 | A .cube LUT as an Image Control look, custom slot name and icon, the five Monochrome looks | Writes a modified firmware file | None listed | 33 | 2026-10-11 |
|---|
| GR4-XPanUnlock | GR IV (standard colour model), firmware 1.11 | A 65:24 XPan crop as a native aspect ratio | Patches the original firmware | None listed | 9 | 2026-10-11 |
|---|
| GR4-MonoUnlock | GR IV (standard colour model), firmware 1.11 | Six GR IV Monochrome looks on a colour GR IV | Patches the original firmware | None listed | 12 | 2026-10-11 |
|---|
| GR4-GF2Unlock | GR IV (standard colour model), firmware 1.11 | GF-2 Flash Mode (distance-based flash exposure) | Patches the original firmware | None listed | 6 | 2026-10-13 |
|---|
| GR4-WebCam | GR IV, firmware 1.11 | Browser remote control and photo download over Wi-Fi | Patches the firmware, plus files on the card | None listed | 1 | 2026-10-16 |
|---|
| GR4-DOOM | GR IV, firmware 1.11 | A game loader | Patches the original firmware | None listed | 1 | 2026-10-13 |
|---|
| ricoh-gr4-hlg-mod | GR IV standard edition, firmware 1.11 | HDR Tone slot becomes an HLG HDR JPEG look | Writes a modified firmware file | None listed | 0 | 2026-10-17 |
|---|
| GR-DLC | GR IIIx HDF 1.60; GR IV, GR IV HDF 1.11 | Nine film slots, custom ratios, power-off picture, recipe tag in the JPEG | Writes a modified firmware file | GPL-2.0 | 1 | 2026-10-14 |
|---|
| m10v | GR III 2.10, GR IIIx 1.60, GR IV 1.11; GR II 3.00 read-only | Film library in five slots, grain, soft light, date stamp, 65:24 on GR IV | Writes a modified firmware file (GR II: nothing) | GPL-2.0 | 4 | 2026-10-19 |
|---|
| GR3-LUTSmith | GR III series 2.10, GR IIIx series 1.60 | A .cube LUT in one Image Control look, custom name and icon | Writes a modified firmware file | None listed | 8 | 2026-10-12 |
|---|
| DARKSLIDE GR | GR III 2.10, GR IIIx 1.60 | 16 built-in film looks or your LUT in four presets, icons, names, power-off picture, grain | Writes a modified firmware file | GPL-2.0 | 26 | 2026-10-17 |
|---|
| GR III / GR IIIx Look Editor | GR III 2.10, GR IIIx 1.60 | Custom look in the Cross Process slot, optional movie M mode | Writes a modified firmware file | MIT | 11 | 2026-10-16 |
|---|
| gr3-film-mods | GR III, firmware 2.10 | Film looks as new Image Control entries, hue sectors, RAW noise reduction | Writes a modified firmware file | MIT (fit data under CC BY-SA 4.0 / CC BY-NC-SA 4.0) | 28 | 2026-10-12 |
|---|
| gr3-12-boxes | GR III (plain model only), firmware 2.10 | 12 User Mode settings boxes instead of 6 | Writes a modified firmware file | MIT | 3 | 2026-10-17 |
|---|
| GR III Film Simulation (gr3-film-sim-firmware) | GR III, GR III HDF, firmware 2.10 | Four new Image Control looks with nine adjustable parameters | Ships a modified firmware file | None listed for the firmware | 7 | 2026-10-09 |
|---|
| GR Tools | GR III, firmware 2.10 | Four style slots from your own looks | Builds a modified firmware file | AGPL-3.0 (firmware part GPL-2.0) | 2 | 2026-10-11 |
|---|
| gr3-filmlut-mods | GR III, firmware 2.10 | Three film looks, grain on film slots, LUT / XMP import | Writes a modified firmware file | GPL-2.0 (film data all rights reserved) | 0 | 2026-10-15 |
|---|
| gr3x-fw-play | GR IIIx (standard model), firmware 1.60 | Eight added film looks, power-off picture (separate script package) | Ships a modified firmware file | GPL-2.0 | 2 | 2026-10-18 |
|---|
| GR Color Studio | GR IV (experimental camera write); GR III photos on the computer only | Colour table swap (GR IV, experimental), presets on photos | GR IV: writes inside the camera (experimental) | None listed | 0 | 2026-10-05 |
|---|
| FRAME (FRAME-GR2) | GR II, on top of Ricoh firmware 3.00 | Custom filters in 16 slots, negative look, HDF-style glow, grain, frames, power-off picture and sound | Ships a modified firmware file | None listed | 165 | 2026-10-19 |
|---|
| ricoh-gr2-boot-screen-mod | GR II, firmware 3.00 | Start-up picture | Card script (proposed); a modified firmware path is marked unsafe | None listed | 0 | 2026-10-09 |
|---|
| GR IV firmware analysis and feature expansion | GR IV family; GR IIIx Urban Edition and GR IIIx HDF 1.60 power-off records | Research notes, custom power-off picture | No installable firmware; scripts write files inside the camera | Noncommercial source licence (earlier revisions Apache-2.0) | 112 | 2026-10-16 |
|---|
| GR3/3X power-off picture (AlexMimi) | GR IIIx 1.60, GR III 2.10 and their editions | Power-off picture | Card script writes inside the camera | None listed | 1 | 2026-10-11 |
|---|
| GR III 2.10 power-off picture tool | GR III (plain model), firmware 2.10 | Power-off picture | Card script writes inside the camera | Noncommercial source licence | 1 | 2026-10-05 |
|---|
| GRKit | GR IV 1.11 / 1.20, GR IIIx 1.60 / 1.70, GR III 2.10 / 2.20, their HDF models, GR IV Monochrome | Film looks with viewfinder preview, extra frame ratios, guides, date imprint, grain, in a sixth ADJ entry | Firmware untouched; a card script patches memory until power-off and turns on the SD script setting, which stays on | MIT (film looks CC BY-SA 4.0 or MIT) | 75 | 2026-10-24 |
|---|
| gr3x-fw-hack | GR III, GR IIIx | Nothing; firmware analysis on a computer | Nothing goes on the camera | None listed | 55 | 2026-02-13 |
|---|
| gr_unpack | GR III | Nothing; an unpacker | Nothing goes on the camera | None listed | 10 | 2020-01-26 |
|---|
| GR III firmware research skill | GR III (standard), firmware 2.10 | Nothing; notes and checks | Nothing goes on the camera | MIT | 4 | 2026-10-11 |
|---|
| QEMU Everything | GR IV 1.11, GR III 2.10, GR IIIx 1.60 | Nothing; runs firmware in an emulator | Nothing goes on the camera | AGPL-3.0 | 1 | 2026-10-16 |
|---|
| GRsync | GR II, GR III | Nothing on the camera | Nothing; reads photos over Wi-Fi | MIT | 104 | 2026-02-11 |
|---|
| RICOH GR Bluetooth API | GR II, GR III, GR IIIx | Nothing on the camera | Nothing | Unlicense | 62 | 2024-11-14 |
|---|
| RICOH Camera Wireless Protocol | README does not name a body | Nothing on the camera | Nothing | None listed | 14 | 2023-06-21 |
|---|
Firmware mods that write to the camera
These build or ship a modified firmware file that goes through the camera’s own update. Highest risk: a bad file can stop the camera from starting.
A desktop app for Windows, macOS and Linux that writes a modified GR IV firmware file. It imports .xmp and .cube looks as up to six new Image Control slots, adds crop ratios such as 65:24 (ported from gr-custom-tool), soft focus on the ADJ lever, a date imprint, halation on the added slots and, from 0.8.0, up to eight power-off pictures picked in the camera menu. It can also make the GR IV Monochrome’s looks selectable on the colour bodies. Release notes are written in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV, GR IV HDF, firmware 1.11
- What it changes: Imported .xmp / .cube looks in up to six new slots, extra aspect ratios, ADJ soft focus, date imprint, power-off pictures, mono looks on colour bodies
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): README: a user installed a 0.2.x build and shot in the added ratios; 0.5.2 soft focus tried on a camera; added slots tried on a GR IV HDF (test firmwares 022 to 034); menus and the power-off picture list checked in an emulator.
- Trouble on record: README: 0.5.0 and 0.5.1 froze the camera with soft focus on the ADJ lever; test firmware 022 stopped the camera on the first ADJ highlight of a new slot; before 0.7.1, in-camera RAW development of an added look stopped the camera; magnifying photos in an added ratio got stuck on 0.2.x. Release 0.7.4: going back to Ricoh firmware without first resetting the camera can hang the menus. Release 0.6.1: some new bodies refuse even Ricoh’s 1.11 file.
- Licence: GPL-2.0
- GitHub: 117 stars, last update 2026-10-17, latest release 0.8.0 (17 Oct 2026). Read on GitHub 19 Oct 2026.
A firmware editor that runs in a local browser window. It reads a GR IV 1.11.10.x firmware file and generates a new one with custom crop ratios, power-off pictures and colour looks fitted from Adobe .xmp profiles, plus a file for going back. It only generates files; it does not flash the camera. Its crop code is the base GR Mod ported. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV, firmware 1.11.10.x
- What it changes: Crop ratios, power-off pictures, looks from .xmp profiles, a downgrade-friendly version option
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Author: the public build has not finished an independent end-to-end and real-camera acceptance test; macOS not tested on a real machine.
- Trouble on record: Author: a file that generates fine is no proof it will flash, start or work. Flashing a generated file can cause faults and affect warranty and official support. Before flashing an older fallback file, reset the camera to factory settings or the menus may hang.
- Licence: GPL-2.0
- GitHub: 77 stars, last update 2026-10-17. Read on GitHub 19 Oct 2026.
Fits a .cube LUT to the camera’s colour matrix and tone curves and builds a GR IV firmware that carries it as an Image Control look, usable in stills, movies, the viewfinder and RAW Development. You can rename the slot and give it your own icon. Comes as an app and a command-line tool.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV, GR IV HDF, firmware 1.11
- What it changes: A .cube LUT as an Image Control look, custom slot name and icon, the five Monochrome looks
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Test table: looks, names, icons and going back to official 1.11 tested on a GR IV 1.11; 2.2.0 tested on a GR IV HDF. Some combinations checked offline only.
- Trouble on record: Not for the GR IV Monochrome. Risks section: the camera cannot tell a good file from a damaged one; if an update is interrupted or a file cannot start, the camera may need Ricoh service (not seen in testing).
- Licence: None listed
- GitHub: 33 stars, last update 2026-10-11, latest release 2.2.0 (11 Oct 2026). Read on GitHub 19 Oct 2026.
Adds XPan, a 65:24 panoramic frame, as a fifth aspect ratio after 16:9, with its own label and icon. It works in live view, focusing, saved JPEGs, Instant Review, RAW Development and Crop. Live view shows the whole frame with the area outside the crop dimmed.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV (standard colour model), firmware 1.11
- What it changes: A 65:24 XPan crop as a native aspect ratio
- On the camera: Patches the original firmware
- Author’s test record (not checked by us): Test table: install, menus, saved sizes, Instant Review, RAW Development, Crop and live-view marks tested on a GR IV 1.11; framing grid not yet tested.
- Trouble on record: Cannot be combined with GR4-MonoUnlock. Going back to official firmware with XPan still selected has not been tested. An interrupted update could leave the camera needing Ricoh service (not seen in testing).
- Licence: None listed
- GitHub: 9 stars, last update 2026-10-11. Read on GitHub 19 Oct 2026.
Brings the six black-and-white looks of the GR IV Monochrome to the standard GR IV, in Image Control, RAW Development and (three of them) movie mode.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV (standard colour model), firmware 1.11
- What it changes: Six GR IV Monochrome looks on a colour GR IV
- On the camera: Patches the original firmware
- Author’s test record (not checked by us): Test table: Standard, Soft, High Contrast and Solid tested on a GR IV 1.11; going back to 1.11 tested; Monochrome HDR not yet tried on a camera.
- Trouble on record: Monochrome HDR is experimental. An interrupted update could leave the camera needing Ricoh service (not seen in testing).
- Licence: None listed
- GitHub: 12 stars, last update 2026-10-11. Read on GitHub 19 Oct 2026.
Adds the GR III’s GF-2 Flash Mode to the GR IV as a fifth flash mode: the flash fires at a fixed power and the camera sets aperture, ISO and shutter from the focus distance.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV (standard colour model), firmware 1.11
- What it changes: GF-2 Flash Mode (distance-based flash exposure)
- On the camera: Patches the original firmware
- Author’s test record (not checked by us): Camera tests were done with version 1.0.0 on a GR IV 1.11; later changes (manual flashes, guide number, ND Auto) checked offline only.
- Trouble on record: The camera cannot tell whether the flash will fire, so a shot can come out too dark. Not combinable with GR4-MonoUnlock or GR4-XPanUnlock. Going back with GF-2 Flash Mode still selected has not been tested.
- Licence: None listed
- GitHub: 6 stars, last update 2026-10-13. Read on GitHub 19 Oct 2026.
An opt-in add-on that makes the GR IV serve a web page over its own Wi-Fi network: live view, shutter, exposure settings and a photo browser in a phone browser, with no app. A file on the card switches it on and off.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV, firmware 1.11
- What it changes: Browser remote control and photo download over Wi-Fi
- On the camera: Patches the firmware, plus files on the card
- Author’s test record (not checked by us): README does not include a test table.
- Trouble on record: Author: installing a modified firmware is at your own risk; Ricoh’s 1.11 file is the way back. The camera’s network uses a fixed password and no pairing.
- Licence: None listed
- GitHub: 1 star, last update 2026-10-16. Read on GitHub 19 Oct 2026.
Adds a small game loader to the GR IV firmware so the camera can run DOOM from the card on the rear screen, played with the camera’s buttons. The game and its data are not in the repo. Ported by the author named in the README.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV, firmware 1.11
- What it changes: A game loader
- On the camera: Patches the original firmware
- Author’s test record (not checked by us): Test table: install, start, controls and going back to 1.11 tested on a GR IV 1.11; saving and Auto Power Off checked offline only.
- Trouble on record: The game runs beside the camera software; if the camera is not usable after leaving the game, the author says to take the battery out.
- Licence: None listed
- GitHub: 1 star, last update 2026-10-13. Read on GitHub 19 Oct 2026.
Replaces the HDR Tone look with an HLG (BT.2100) curve and writes an HDR display profile into the JPEG, so phones and computers that support HDR photos show it as HDR. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV standard edition, firmware 1.11
- What it changes: HDR Tone slot becomes an HLG HDR JPEG look
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): README: hardware test marked passed (live view, playback, export to an HDR phone).
- Trouble on record: README describes the checksum work as zero risk. We do not take any firmware patch as zero risk. Created 17 Oct 2026, no stars yet.
- Licence: None listed
- GitHub: 0 stars, last update 2026-10-17. Read on GitHub 19 Oct 2026.
A fork of GR Mod maintained separately. It adds nine film slots with a 120-entry film catalogue (you bring your own .cube files), custom ratios and power-off pictures, and ports the work to the GR IIIx HDF. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IIIx HDF 1.60; GR IV, GR IV HDF 1.11
- What it changes: Nine film slots, custom ratios, power-off picture, recipe tag in the JPEG
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): GR IIIx HDF: user feedback on the camera for part of the films and settings. GR IV: nine-slot combination not yet tested on a camera.
- Trouble on record: Author: preview release; camera feedback does not cover all 120 looks or every ratio combination. Modified firmware carries risk; no maker warranty.
- Licence: GPL-2.0
- GitHub: 1 star, last update 2026-10-14, latest release 0.1.0 (14 Oct 2026). Read on GitHub 19 Oct 2026.
A web workbench that builds firmware with a 65-look film library in five slots, grain and soft light per slot, and a date stamp. GR II files can only be inspected. Named after the hostname found inside the GR III firmware. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III 2.10, GR IIIx 1.60, GR IV 1.11; GR II 3.00 read-only
- What it changes: Film library in five slots, grain, soft light, date stamp, 65:24 on GR IV
- On the camera: Writes a modified firmware file (GR II: nothing)
- Author’s test record (not checked by us): Author: status is waiting for real-camera tests; still JPEG film processing confirmed in real shots.
- Trouble on record: Author: flashing can stop the camera from starting, lose data or brick it, and recovery cannot be guaranteed. An optional version-lock bypass is off by default.
- Licence: GPL-2.0
- GitHub: 4 stars, last update 2026-10-19. Read on GitHub 19 Oct 2026.
The GR III and GR IIIx version of GR4-LUTSmith: fits a .cube LUT and builds firmware in which one Image Control look carries it, in stills, movie, viewfinder and RAW Development.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III series 2.10, GR IIIx series 1.60
- What it changes: A .cube LUT in one Image Control look, custom name and icon
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Version 1.0.0: checked offline; not yet tested on a real camera. An earlier test file was installed on a GR III and removed again.
- Trouble on record: No firmware made by this version has been installed on a camera yet. An interrupted update could leave the camera needing Ricoh service.
- Licence: None listed
- GitHub: 8 stars, last update 2026-10-12. Read on GitHub 19 Oct 2026.
A local browser editor that puts film looks or your own LUT into four GR III / GR IIIx presets, and changes preset icons, names, the power-off picture and negative-film grain. It outputs a firmware file and does not touch the camera or the card. README in Chinese, English version in the repo.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III 2.10, GR IIIx 1.60
- What it changes: 16 built-in film looks or your LUT in four presets, icons, names, power-off picture, grain
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Author flashed one GR III (2.10): icons, names, power-off picture, grain and going back to official 2.10 showed no problems. GR III editions, HDF and every GR IIIx not tested.
- Trouble on record: Author: the camera may not start, may stop working or may be bricked for good, and warranty may be lost. Sample size is one camera.
- Licence: GPL-2.0
- GitHub: 26 stars, last update 2026-10-17, latest release 1.0.0 (17 Oct 2026). Read on GitHub 19 Oct 2026.
Builds your own look into the Cross Process slot, with a live preview on your own DNG that runs the camera’s tone-curve code. An option also enables manual exposure in movie mode and a higher 24/30p bitrate.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III 2.10, GR IIIx 1.60
- What it changes: Custom look in the Cross Process slot, optional movie M mode
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): The modified update has been tested on one GR III and one GR IIIx.
- Trouble on record: Author: can leave the camera unusable in the worst case, and there is no known recovery procedure yet.
- Licence: MIT
- GitHub: 11 stars, last update 2026-10-16. Read on GitHub 19 Oct 2026.
Image-pipeline research tools that add film looks (Portra 400, Ektar 100, Gold 200, Pro 400H, Vision3 250D / 500T, Classic Neg) as new Image Control entries and change RAW noise reduction on the GR III. Several other GR III and GR IIIx projects build on it.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III, firmware 2.10
- What it changes: Film looks as new Image Control entries, hue sectors, RAW noise reduction
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Checked by offline emulation and on a single camera. Colour results measured on the camera.
- Trouble on record: Author: flashing can permanently brick the camera, damage hardware, corrupt images or settings, and will almost certainly void the warranty.
- Licence: MIT (fit data under CC BY-SA 4.0 / CC BY-NC-SA 4.0)
- GitHub: 28 stars, last update 2026-10-12. Read on GitHub 19 Oct 2026.
An offline patcher that raises the GR III’s User Mode settings boxes from 6 to 12; U1 to U3 can each use any of the 12. It can patch the stock file or a gr3-film-mods build.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III (plain model only), firmware 2.10
- What it changes: 12 User Mode settings boxes instead of 6
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Checked offline and on a single camera, for each supported input.
- Trouble on record: Author: can permanently brick the camera. The GR III has a single firmware bank, so an image that does not reach the menu cannot be reflashed from the camera.
- Licence: MIT
- GitHub: 3 stars, last update 2026-10-17. Read on GitHub 19 Oct 2026.
Research notes plus ready-made experimental firmware releases that add four film-inspired looks (Gold 200, Tungsten 800, Ektar 100, Metropolis) to the GR III. README in Chinese and English.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III, GR III HDF, firmware 2.10
- What it changes: Four new Image Control looks with nine adjustable parameters
- On the camera: Ships a modified firmware file
- Author’s test record (not checked by us): Maintainer reported on 9 Oct 2026 that V9.2 keeps its settings after a restart. Full camera matrix, power-loss and long-term tests not done.
- Trouble on record: README: V9 had a RAW Image Control screen corruption and power-off problem; V9.1 lost settings on restart. No promise of rollback or rescue.
- Licence: None listed for the firmware
- GitHub: 7 stars, last update 2026-10-09, latest release V9.2 experimental (9 Oct 2026). Read on GitHub 19 Oct 2026.
Browser tools from the same author: GR Studio makes a look from a DNG, GR Firmware builds a camera update with four style slots from your own official file.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III, firmware 2.10
- What it changes: Four style slots from your own looks
- On the camera: Builds a modified firmware file
- Author’s test record (not checked by us): README: each candidate needs its own camera acceptance; offline checks do not establish reboot behaviour or stability.
- Trouble on record: README does not list camera faults.
- Licence: AGPL-3.0 (firmware part GPL-2.0)
- GitHub: 2 stars, last update 2026-10-11. Read on GitHub 19 Oct 2026.
A fork of gr3-film-mods that adds three film looks with their own fit data, an in-camera grain setting for the film slots, and a local web build tool.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III, firmware 2.10
- What it changes: Three film looks, grain on film slots, LUT / XMP import
- On the camera: Writes a modified firmware file
- Author’s test record (not checked by us): Verified only by offline emulation and on a single camera.
- Trouble on record: Author: can permanently brick the camera and voids warranty.
- Licence: GPL-2.0 (film data all rights reserved)
- GitHub: 0 stars, last update 2026-10-15. Read on GitHub 19 Oct 2026.
Takes gr3-film-mods to the GR IIIx: 22 Image Controls (12 stock, 2 custom, 8 added film looks) and ships ready-made firmware. A separate package changes the power-off picture through a camera script. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IIIx (standard model), firmware 1.60
- What it changes: Eight added film looks, power-off picture (separate script package)
- On the camera: Ships a modified firmware file
- Author’s test record (not checked by us): B2.4.2: a test user confirmed loading, power on/off and RAW / JPEG output on 17 Oct 2026. Continuous shooting and long-term stability not covered.
- Trouble on record: B2.4.1 had a layout conflict. Author: going back to Ricoh’s firmware only works while the update screen can still be reached, and the full recovery has not been tested.
- Licence: GPL-2.0
- GitHub: 2 stars, last update 2026-10-18, latest release B2.4.2 (17 Oct 2026). Read on GitHub 19 Oct 2026.
A modified GR II firmware with companion apps (Android, macOS, Windows, iPhone beta) that load up to 16 custom filters from .cube / XMP into the camera over Wi-Fi, add negative-film and HDF-style looks, grain, photo frames and custom power-off pictures and sounds. The most-starred GR firmware project on GitHub when we looked. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR II, on top of Ricoh firmware 3.00
- What it changes: Custom filters in 16 slots, negative look, HDF-style glow, grain, frames, power-off picture and sound
- On the camera: Ships a modified firmware file
- Author’s test record (not checked by us): README shows camera photos and the author’s release notes; no test table.
- Trouble on record: The repo publishes builds and documentation but no source code. README asks for a full battery and no power loss during the update; it gives no brick or recovery notes.
- Licence: None listed
- GitHub: 165 stars, last update 2026-10-19, latest release WN3 firmware (10 Oct 2026), app 1.0.3 (18 Oct 2026). Read on GitHub 19 Oct 2026.
Card scripts that write inside the camera
These leave the firmware file alone but use a script on the card or a factory interface to replace files inside the camera, such as the power-off picture, or to patch the camera’s memory until it turns off. Still unofficial, still able to break things.
A Windows app for colour presets on JPG and DNG files and .cube export. It also has an experimental wizard to back up, replace and restore the GR IV’s in-camera colour table, a tool that writes a factory-menu entry file, and a firmware unpacker. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV (experimental camera write); GR III photos on the computer only
- What it changes: Colour table swap (GR IV, experimental), presets on photos
- On the camera: GR IV: writes inside the camera (experimental)
- Author’s test record (not checked by us): GR III factory-menu entry tested on a camera. README does not give GR IV test results.
- Trouble on record: README does not list faults. Marked experimental.
- Licence: None listed
- GitHub: 0 stars, last update 2026-10-05. Read on GitHub 19 Oct 2026.
Firmware analysis of the GR II with two ways to change the start-up picture: a startup script on the card, or a rebuilt firmware file. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR II, firmware 3.00
- What it changes: Start-up picture
- On the camera: Card script (proposed); a modified firmware path is marked unsafe
- Author’s test record (not checked by us): Author: every conclusion comes from offline static analysis; nothing verified on a camera.
- Trouble on record: Author: the firmware path cannot be run safely yet because an update checksum is not solved, and flashing it could brick the camera.
- Licence: None listed
- GitHub: 0 stars, last update 2026-10-09. Read on GitHub 19 Oct 2026.
The research repo much of the GR IV work cites: firmware container, Linux memory, USB, factory and debug interfaces, the GF-2 hotshoe and model IDs. Custom power-off pictures go in through the camera’s factory-script interface. Most reports are in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV family; GR IIIx Urban Edition and GR IIIx HDF 1.60 power-off records
- What it changes: Research notes, custom power-off picture
- On the camera: No installable firmware; scripts write files inside the camera
- Author’s test record (not checked by us): The GR IIIx HDF record is one body; its restore was not tested. Newer templates not fully camera-qualified.
- Trouble on record: Author: camera modifications risk data loss or malfunction; results apply only to the documented setups.
- Licence: Noncommercial source licence (earlier revisions Apache-2.0)
- GitHub: 112 stars, last update 2026-10-16. Read on GitHub 19 Oct 2026.
A single web page that fits your picture and builds a card package that replaces the GR III / GR IIIx power-off picture through the camera’s script function. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IIIx 1.60, GR III 2.10 and their editions
- What it changes: Power-off picture
- On the camera: Card script writes inside the camera
- Author’s test record (not checked by us): Only the standard GR IIIx 1.60 install has been tested on a camera.
- Trouble on record: README: reinstalling official firmware does not always restore the original power-off picture; use the restore option instead.
- Licence: None listed
- GitHub: 1 star, last update 2026-10-11. Read on GitHub 19 Oct 2026.
A desktop tool that encodes a power-off picture and builds card packages to back up, replace and read back the GR III’s power-off picture. Based on the GR IV research repo above. README in Chinese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR III (plain model), firmware 2.10
- What it changes: Power-off picture
- On the camera: Card script writes inside the camera
- Author’s test record (not checked by us): One GR III 2.10 body verified; one-shot install reported working by a user, without logs.
- Trouble on record: README: a length check is not a full content check and does not guarantee every fault can be recovered. Other bodies and general restore not verified.
- Licence: Noncommercial source licence
- GitHub: 1 star, last update 2026-10-05, latest release 0.1.1 (5 Oct 2026). Read on GitHub 19 Oct 2026.
An SD-card plugin system that adds a sixth ADJ entry, GRK, with five modules picked when the package is built on grkit.app: film looks in Image Control with a viewfinder preview, framing (65:24 XPan, 2.35:1, 16:9, 4:3, 5:4, 1:1), guides, a date imprint and grain. It does not write the camera firmware: it loads from the card a few seconds after each power-on and changes the camera’s memory until it turns off. 16 film looks at 1.0.0; 1.2.1 added five and dropped three. The look fitting is ported from gr3-film-mods. README in English, Chinese and Japanese.
Unofficial firmware. Can freeze or brick the camera. We have not flashed it.
- Cameras: GR IV 1.11 / 1.20, GR IIIx 1.60 / 1.70, GR III 2.10 / 2.20, their HDF models, GR IV Monochrome
- What it changes: Film looks with viewfinder preview, extra frame ratios, guides, date imprint, grain, in a sixth ADJ entry
- On the camera: Firmware untouched; a card script patches memory until power-off and turns on the SD script setting, which stays on
- Author’s test record (not checked by us): README: GR III 2.10 and GR IV 1.11 tested on a camera. Other supported bodies run the same runtime but are not tested themselves. 2.20, 1.70 and 1.20 have not been tested on a camera. Changelog 1.0.1: GR IV 1.11 marked tested after a user report.
- Trouble on record: README: experimental, use at your own risk; if GRKit fails the camera can stop during startup, so read the recovery guide first. Deleting the SCRIPT folder from the card removes it. Changelog: 1.1.1 stopped GR IV / HDF from halting on another build of 1.11; 1.2.0 starts 2 seconds later to avoid a stop when the script talks to the camera before it is ready.
- Licence: MIT (film looks CC BY-SA 4.0 or MIT)
- GitHub: 75 stars, last update 2026-10-24, latest release 1.2.1 (24 Oct 2026). Read on GitHub 24 Oct 2026.
Research: nothing goes on the camera
Notes, unpackers and emulators that read firmware on a computer.
Exploration of the GR III / GR IIIx firmware, aiming to run custom applications without altering the firmware, in the spirit of Magic Lantern. Includes extraction tools and a Docker environment; the system does not fully boot there yet.
- Cameras: GR III, GR IIIx
- What it changes: Nothing; firmware analysis on a computer
- On the camera: Nothing goes on the camera
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: Research only.
- Licence: None listed
- GitHub: 55 stars, last update 2026-02-13. Read on GitHub 19 Oct 2026.
Documents and decodes the packing of GR III firmware images. One of the oldest public pieces of GR firmware research (January 2020).
- Cameras: GR III
- What it changes: Nothing; an unpacker
- On the camera: Nothing goes on the camera
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: Research only.
- Licence: None listed
- GitHub: 10 stars, last update 2020-01-26. Read on GitHub 19 Oct 2026.
Research notes on GR III 2.10 firmware packaged for coding agents. It explicitly ships no firmware builder, no modified firmware and no flashing tool.
- Cameras: GR III (standard), firmware 2.10
- What it changes: Nothing; notes and checks
- On the camera: Nothing goes on the camera
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: Author: modifying firmware can brick the camera permanently, and a complete boot failure has no verified recovery path.
- Licence: MIT
- GitHub: 4 stars, last update 2026-10-11. Read on GitHub 19 Oct 2026.
A multi-brand firmware emulation workbench. For Ricoh it boots the GR III / GR IIIx Linux side and opens one original GR IV 1.11 menu in an emulator.
- Cameras: GR IV 1.11, GR III 2.10, GR IIIx 1.60
- What it changes: Nothing; runs firmware in an emulator
- On the camera: Nothing goes on the camera
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: Research only.
- Licence: AGPL-3.0
- GitHub: 1 star, last update 2026-10-16. Read on GitHub 19 Oct 2026.
Related tools that do not change firmware
Wi-Fi and Bluetooth references. They talk to the stock camera.
A Python script that copies photos from a GR II or GR III over the camera’s Wi-Fi. It does not edit firmware.
- Cameras: GR II, GR III
- What it changes: Nothing on the camera
- On the camera: Nothing; reads photos over Wi-Fi
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: None recorded.
- Licence: MIT
- GitHub: 104 stars, last update 2026-02-11. Read on GitHub 19 Oct 2026.
An unofficial list of the Bluetooth characteristics of Ricoh and Pentax cameras, from reverse engineering.
- Cameras: GR II, GR III, GR IIIx
- What it changes: Nothing on the camera
- On the camera: Nothing
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: Author: use at your own risk.
- Licence: Unlicense
- GitHub: 62 stars, last update 2024-11-14. Read on GitHub 19 Oct 2026.
An OpenAPI description of the Wi-Fi HTTP interface, reverse engineered from Ricoh’s Image Sync app. The Bluetooth part is marked in progress.
- Cameras: README does not name a body
- What it changes: Nothing on the camera
- On the camera: Nothing
- Author’s test record (not checked by us): Not applicable.
- Trouble on record: None recorded.
- Licence: None listed
- GitHub: 14 stars, last update 2023-06-21. Read on GitHub 19 Oct 2026.
What we left out
- Download sites and repackaged builds whose repo does not describe changes of their own (for example a GR Mod repackage with a different interface language, and a site that hosts a GR IV film firmware).
- Projects for cameras outside the GR line: Ricoh GXR colour-recipe research, and Sony PlayMemories apps with GR-style colour.
- Recipe lists and settings guides that do not touch firmware, and companion photo apps.
- Gadget firmware that runs on another device, such as the M5Stack live-view remotes. Those are on the GR tools page.
GR custom firmware FAQ
Is there custom firmware for the Ricoh GR IV?
Yes, unofficial. GR Mod, gr-custom-tool, GR4-LUTSmith, GR4-XPanUnlock, GR4-MonoUnlock, GR4-GF2Unlock and a few more build a modified file from Ricoh’s firmware 1.11. Most name the standard GR IV; GR Mod and GR4-LUTSmith also name the GR IV HDF. GRKit adds film looks and framing from the card without changing the firmware file.
Is there custom firmware for the GR III or GR IIIx?
Yes. For the GR III on 2.10 there are DARKSLIDE GR, the Look Editor, gr3-film-mods, gr3-12-boxes, GR3-LUTSmith and others. For the GR IIIx on 1.60 there are gr3x-fw-play, the Look Editor, GR3-LUTSmith and GR-DLC (HDF). Most say they were tested on one camera, and some versions not on any.
Can I add a 65:24 XPan crop, a LUT or a date stamp to the GR IV?
Only through unofficial tools. GR4-XPanUnlock and GR Mod add 65:24. GR Mod and GR4-LUTSmith turn a .cube file into an Image Control look. GR Mod and m10v add a date imprint. GRKit does all three from a card script without changing the firmware file, on the GR III, GR IIIx and GR IV. Ricoh’s own firmware does none of these.
Can GR custom firmware brick the camera?
The authors say it can. GR Mod’s own README records builds that froze the camera. gr3-12-boxes notes the GR III has one firmware bank, so a file that never reaches the menu cannot be reflashed from the camera. The Look Editor and the GR III research skill say there is no known recovery for a camera that will not start.
Should I trust a README that says a mod is safe?
Not on its own. A README is the author describing their own work. Most authors here tested on one camera, some on none, and one README calls its patch zero risk. We have not checked any of these claims. Read them, and the trouble notes, as one person’s report.
Does Ricoh support it, and is my warranty safe?
No. None of these projects is made or endorsed by Ricoh, and several READMEs warn that modified firmware may void the warranty. Several advise going back to Ricoh’s official firmware before sending a camera for service.
Is there anything for the GR IV Monochrome, the 2013 GR or the GR Digital?
Firmware mods, no. GR IV Monochrome owners are told to stay away by several GR IV tools. GRKit, a card script, names the Monochrome without its film looks. We found nothing for the 2013 GR or any GR Digital.
GR firmware log · GR tools page · Ricoh GR