📖 Flipper Seos

August 29, 2026 · View on GitHub

Flipper app for reading and emulating Seos®-compatible cards/fobs/mobile credentials.

🔑 Keys

The app uses all zero keys by default. If you'd like to use your own keys/ADF OID, use the format of the keys-example.txt to specify them, and place into SD Card/apps_data/seos/.

No key files: If no key files are present, the app defaults to all zeros (00) for keys and an ADF OID of 030107090000000000 ("0.3.1.7.9.0.0.0.0.0").
keys.txt: If keys.txt is present in SD Card/apps_data/seos/, it is automatically loaded at launch
Additional key sets: Other key files named *_keys.txt (e.g., work_keys.txt, home_keys.txt) can be placed in the same directory and selected via the Key Switcher in the app menu

This software incorporates a third-party implementation of Seos® technology. It is not developed, authorized, licensed, or endorsed by HID Global®, ASSA ABLOY®, or any of their affiliates. References to Seos® are solely for descriptive and compatibility purposes.

No guarantee of compatibility or functionality is made. This implementation may not work with all Seos®-enabled systems, and its performance, security, and reliability are not assured. Users assume all risks associated with its use.

Seos®, HID Global®, and ASSA ABLOY® are trademarks or registered trademarks of their respective owners. This software is not associated with or sponsored by them in any way.

🛠️ To do:

Fix iso14443a-4 framing
ASN.1 for serializing/deserializing
Support for larger message wrapping/unwrapping
When parsing incoming data, use buffer + len instead of BitBuffer so I can increment buffer pointer as I parse header(s)
CMAC checking where I missed it
Confirm the larger frame size and the block replies against a real reader

🧪 Tests

make test-host builds and runs the suite on this machine. make test-asan runs it again under the address and undefined behaviour sanitisers, which is what makes the truncation sweeps prove a parser did not read past its buffer. make coverage reports what the app's own sources have covered.

📡 External BLE

The nRF52840 dongle is off by default. Turn it on with External BLE in the main menu; the choice is saved. While it is off the dongle's stack is never loaded and costs nothing, the scanners are hidden, and BLE emulation uses the Flipper's own radio.

Both BLE stacks ship inside the .fap as plugins and are loaded only while a BLE screen is open.

💡 Hardware for BLE support (experimental)

Install/setup Nordic SDK
Install Toolchain manager
Launch Toolchain manager
Next to SDK version click down arrow and "open terminal"
Navigate to samples/bluetooth/hci_uart_3wire
Build with west build -b nrf52840dk_nrf52840 -p auto
west flash

🧪 nRF52840

Edit boards/nrf52840dk_nrf52840.overlay and change current speed to 460800 to match Flipper app.
west build -b nrf52840dk_nrf52840 -p auto
west flash

🦝 nRF52840 dongle

Copy boards/nrf52840dongle_nrf52840.overlay to hci_uart_3wire
May need to: nrfutil install nrf5sdk-tools
west build -b nrf52840dongle_nrf52840 -p auto
nrfutil nrf5sdk-tools pkg generate --hw-version 52 --sd-req=0x00 --application ./build/hci_uart_3wire/zephyr/zephyr.hex --application-version 1 app.zip
Put dongle into DFU by pressing 'reset' button
nrfutil nrf5sdk-tools dfu usb-serial -pkg app.zip -p /dev/cu.usbmodemD39BF26162261

🔌 Connection

flipper purpose	pin	color	nRF52840 dk pin	nRF52840 dongle pin
rx	16	yellow	P0.06	P0.20
tx	15	orange	P0.08	P0.24
gnd	11	black	any ground	GND
power	5v	red	VIN 3-5v	VBUS