# X-T5 firmware modding: recovery, backups and safer approaches (research 2026-11-06)

Public version from AI for Mortals. Educational use only, at your own risk. High-level research notes, not instructions.

Bottom line: nobody has run custom code on any X-Processor 5 body (X-T5, X-H2, X-S20, X-T50, X100VI). There is no
public way to recover an X-T5 whose boot is broken by a modified firmware. Everything read-only is safe; flashing a
modified file is the one high-risk step.

## How X-T5 firmware updates work
- Update from the SD card: hold DISP/BACK while powering on, or SET UP > USER SETTING > FIRMWARE UPDATE (menu option
  since v3.01). Phone app updates also exist. Manual: https://fujifilm-dsc.com/en/manual/x-t5/technical_notes/firmware_version/
- Current release 4.31, file FWUP0030.DAT. https://www.fujifilm-x.com/global/support/download/firmware/cameras/x-t5/
- Fuji's warnings: charged battery; don't power off or touch it during the update (~10 min, EVF blank); "If the
  camera is turned off during a firmware update, the camera may no longer operate normally"; "It is not possible to
  return to a previous version after the firmware has been updated."
- Unverified: whether the same version can be re-installed; whether the updater is separate from the main firmware.
- App updates have frozen bodies before (Fuji notice, Jan 2023): use the SD card. https://fujifilm-x.com/fr-fr/global-news/2023/0119_4212468/

## Why "just reinstall the firmware" may not save it
- Reinstalling needs the camera to boot far enough to read the card and run the updater. A modified image that breaks
  boot or the updater means the official file can't load. (Inference, not documented by Fuji.)
- FujiHack: custom firmware "is always dangerous"; boot-ROM recovery exists in principle but "hasn't been
  reverse-engineered yet". https://github.com/fujihack/fujihack
- fffw's bricked-camera recovery tool (ffre) is unpublished/abandoned, only partly tested on an X-E2. https://github.com/tiredboffin/fffw
- No public Fuji service/factory recovery mode. Repair = send to Fuji (forum reports: X-H1 board ~$325; an X-H2S dead
  after an app update took ~2 weeks just to be looked at). No public report found of a Fuji bricked by a mod.

## Safer approaches (load from card into memory, never write flash)
- FujiMod dual-boots from the SD card and runs code in RAM, leaving stock firmware untouched, on EXR II bodies (X70).
  X-T5: "Not started". Its warning: don't flash custom firmware without dual booting first. https://fujimod.com https://github.com/justjake/fujimod
- Magic Lantern pattern: a one-time flag, then boots from the card; a card without it boots stock Canon.
- fpSup (Sigma fp): loads from the card into memory, "does not write to the camera's flash". https://ijigen.github.io/fpSup/
- The safe pattern across communities: load from card into memory, never write flash, never touch the bootloader.
- None of this exists for X-Processor 5 yet. Requirements: the boot ROM loads code from a card, or the USB service
  mode answers; the code is mapped well enough to find the JPEG pipeline.

## X-T5 firmware internals (what's known)
- X-Processor 5 = quad-core AArch64, runs Fuji's RTOS plus Linux. https://wiki.fujihack.org/history/
- Where JPEG / film-sim processing lives: unknown, possibly DSP code not covered by current tools.

## Halation / bloom specifically
- Fuji has shipped a Halation filter on the X half, so Fuji can do it in camera. The X-T5 doesn't have it.
- X-T5 Advanced Filters include Soft Focus and Miniature, which already blur in camera: Soft Focus is the obvious
  candidate to study for bloom. Halation needs a red glow on highlights only (a highlight mask); unknown whether
  the filter code allows that.

## Backups before anything risky
- Settings: CONNECTION MODE -> USB RAW CONV./BACKUP RESTORE, then FUJIFILM TETHER APP (X Acquire's successor)
  save/load. https://fujifilm-dsc.com/en/manual/x-t5/connections/save_load_setting/
- fujicli `backup` (X-T5 extensively tested). po4yka/fuji-cli `backup export` verified on X-T5 4.31; restore only on
  exact 4.31, tied to the camera's serial. A settings backup can't fix a camera that won't boot.
- Keep a copy of the current official FWUP*.DAT. Note the firmware version (SET UP > FIRMWARE VERSION).

## Risk ladder
- Zero risk: backing up settings and reading documentation.
- Low: note firmware version, back up settings, full battery, spare card.
- High: flashing any modified DAT. No rollback, no public recovery.
- Recommended stopping point: don't install anything that isn't Fuji's official firmware.