Xbox POST Code Reader for Flipper Zero

Xbox POST Code Reader turns a Flipper Zero into a portable Xbox boot diagnostic reader. It captures POST traffic directly from a supported Xbox motherboard, keeps a live history, decodes known codes offline, saves sessions to the SD card, and can stream codes over USB to the companion browser tool.

This is a Flipper Zero adaptation of the PicoDurangoPOST project, paired with the online WebXboxPOSTTool.

What it can do

• Emulate the MAX6958 POST display at I2C address 0x38.
• Capture four-digit POST codes without blocking the Flipper controls.
• Show either one current code or a scrolling 128-entry live log.
• Decode selected codes locally using 452 bundled console-aware records.
• Browse known codes by All, POST, Error, SMC, SP, CPU, or OS category.
• Save captures as automatically numbered SD-card logs.
• Browse and read saved logs from the Flipper.
• Stream live codes to WebXboxPOSTTool over USB Web Serial.
• Show Xbox One and Xbox Series wiring directly in the app.
• Display an offline QR code for opening the decoder on a phone.

Screenshots

Captured from the Flipper simulator because the app enters USB UART mode during live capture, which prevents on-device screenshots.

Main Menu	Reader	Known Codes	Wiring

Install the FAP

1. Download xbox_postcode_reader.fap from dist/ or from the WebXboxPOSTTool reader setup page.
2. Connect the Flipper Zero with qFlipper or another SD-card file manager.
3. Copy the FAP to SD Card/apps/GPIO/xbox_postcode_reader.fap.
4. On the Flipper, open Apps > GPIO > Xbox POST Code Reader.

The app is currently version 0.14.

Wiring

Only connect SDA, SCL, and a shared ground.

Signal	Xbox One family (FACET)	Xbox Series S/X (AARDVARK)	Flipper Zero
SDA	Pin 26	Pin 3	GPIO 15 / PC1
SCL	Pin 25	Pin 1	GPIO 16 / PC0
GND	GND	GND	GND

Xbox One, One S, and One X use the FACET connection. Xbox Series S and Series X use AARDVARK. Connector orientation and populated components can vary between motherboard revisions, so locate pin 1 from the board markings before soldering.

Read POST codes

1. Connect SDA, SCL, and GND with the Xbox unplugged.
2. Open Wiring and use Left/Right to select the Xbox model. Confirm the displayed pins.
3. Return to the menu and open Reader. Capture starts automatically.
4. Apply standby power or start the Xbox.
5. Watch the current code, source (SMC, SP, CPU, or OS), segment, and elapsed time.
6. Press Right to decode the selected code locally, or Left to open the rolling log.
7. Press OK to pause capture before changing wiring.

A lack of traffic can also indicate missing standby power or a failed standby rail; it does not always mean the reader is wired incorrectly.

Controls

Reader

Button	Action
OK	Pause or resume capture
Up / Down	Browse captured codes
Hold Up	Save the complete history to the next numbered SD log
Left	Open the rolling live log
Right	Decode the selected code
Hold Left	Open the Clear History confirmation
Back	Return from Decode or Log; from Reader, stop capture and open the menu

On the Decode screen, Up/Down scrolls repair notes, Right changes the selected Xbox model, and Back returns to the Reader screen.

Known Codes

• Left/Right changes the category.
• Up/Down browses records.
• OK opens the highlighted record.
• Up/Down scrolls long repair information.
• Back returns to the list, then to the main menu.

Saved Logs

Hold Up while the Reader or live log contains codes. The app creates post_log_001.txt, post_log_002.txt, and so on without overwriting an earlier capture. Open Saved Logs, choose a file with Up/Down, press OK, and scroll with Up/Down.

Logs are stored in the app data directory under logs/.

Pair the FAP with WebXboxPOSTTool

The browser tool can receive the Flipper's codes live over USB:

Open WebXboxPOSTTool

1. Use desktop Chrome, Edge, or Opera. Web Serial is not available in every browser or on most mobile browsers.
2. Launch Xbox POST Code Reader on the Flipper.
3. Connect the Flipper to the computer by USB.
4. Open WebXboxPOSTTool and select Connect POST Reader.
5. Choose the Flipper serial device in the browser permission dialog.
6. Start the Xbox. Codes will appear in the POST Code Monitor and can be selected for local database details.

The page opens the device at 115200 baud and automatically sends discovery commands. A successful connection reports information similar to:

DEVICE: Xbox POST Code Reader
FW: Xbox POST Code Reader v0.14
CONFIG: console=SERIES X database=452 mode=POST

Supported discovery commands are:

Command	Response
hello	Device identity, firmware, and configuration
version	FAP version
config	Selected console, database size, and capture mode

The selected console follows the model chosen in the Flipper's Wiring or Decode screen. The website also contains the full searchable master database and works without a connected reader for manual lookups.

For phone use, open the same URL manually or scan the QR code shown under Web Decoder in the FAP. The phone page can browse and decode codes, but USB Web Serial generally requires a supported desktop browser.

App menu

Xbox POST Reader
|-- Reader
|-- Known Codes
|-- Saved Logs
|-- Wiring
|-- Web Decoder
`-- About

POST capture, USB transmission, and button input use separate queues. Heavy POST traffic therefore cannot fill the input queue and lock menu navigation.

Local database

The FAP bundles 452 POST records maintained from:

• XboxOneResearch/errorcodes
• TorusHyperV/XboxOne-EXXX-err-Codes

The database includes exact SMC, SP, CPU, and OS errors, normal boot markers, masked boot phases, and AGESA/ABL test points. See data/SOURCES.md for snapshot details.

To regenerate the Flipper and browser databases after updating the source snapshots:

python tools/generate_databases.py --site-dir W:\Demo\WebXboxPOSTTool

Build from source

With uFBT installed:

ufbt

The release FAP is written to dist/xbox_postcode_reader.fap.

From a full Flipper firmware tree, place this directory at applications_user/xbox_postcode_reader and run:

./fbt fap_xbox_postcode_reader

Project layout

.
|-- application.fam             Flipper external-app manifest
|-- main.c                      Capture, UI, USB serial, logs, and QR
|-- postcode_db.c               Generated offline database
|-- postcode_db.h               Database interface
|-- xbox_postcode_reader.png    10x10 application icon
|-- assets/                     Editable monochrome icon source
|-- data/                       Archived upstream database snapshots
|-- tools/                      Database generator
|-- dist/                       Built FAP
|-- CHANGELOG.md
`-- README.md

Credits

• Flipper Zero adaptation and WebXboxPOSTTool: coolshrimp
• Adapted from the PicoDurangoPOST project by XboxOneResearch

Use this project only on hardware you own or are authorized to repair. Xbox and related names are trademarks of Microsoft. This independent community project is not affiliated with or endorsed by Microsoft or Flipper Devices.