YubiKey Expansion Card Adapters

Several community members have created 3D-printed expansion card adapters that house a YubiKey security key inside a Framework laptop's expansion card slot. The YubiKey connects to the internal USB-C port exposed when an expansion module is removed, keeping the key flush with the laptop chassis and protected from snagging or damage¹.

Motivation

Framework laptops expose internal USB-C ports when expansion modules are removed. YubiKey security keys — widely used for two-factor authentication, PGP, and FIDO2 — typically stick out from USB ports, making them vulnerable to damage and inconvenient to leave plugged in. The YubiKey 5C Nano costs approximately $60 USD and still protrudes slightly. Community-designed expansion card shells provide a custom-fit alternative at minimal cost¹²³.

All designs leverage Framework's open-source ExpansionCards reference designs for the card enclosure dimensions⁴.

Projects

Ivan_Grynov's YubiKey 5C Adapter (September 2022)

The first known YubiKey expansion card adapter, created by community member Ivan_Grynov in September 2022¹. Designed in OpenSCAD and translated to OnShape, it is a 3D-printed shell that holds a full-size YubiKey 5C inside the expansion card form factor.

Key design features¹:

• A dedicated hole on the underside allows access to the YubiKey's capacitive touch sensor (reachable from underneath the laptop)
• No supports needed for 3D printing — lay flat on the side with the rectangular YubiKey cutout facing the bed
• STL file shared in the community thread

Stavros' Solo 2 Security Key Adapter (January 2023)

Community member Stavros (Stavros Korokithakis) took a different approach, using a Solo 2 security key instead of a YubiKey³. The Solo 2's form factor proved nearly ideal — its length matched the distance from the internal USB-C port to the outer edge of the laptop almost exactly, and its touch area sits on the outermost edge, making it easy to activate by running a finger across the laptop's side³.

Design details³:

• Top part designed to fit over Framework's provided bottom shell, secured with superglue
• A cylinder passes through the Solokey's keyring hole to hold it in place
• Final version printed in transparent PETG to match the laptop's aluminum appearance and allow visibility of the key's status LED
• The LED proved useful for observing that the USB port retains power for some time after shutdown

moparisthebest's Integrated YubiKey Expansion Card (April 2024)

Community member moparisthebest created the most integrated solution by modifying both the expansion card and the YubiKey itself²⁵. Starting with a disassembled Framework USB-C expansion card, they cut the back off a YubiKey 5C with a Dremel to fit inside the module shell⁵.

The modification process⁵:

1. Disassemble a Framework USB-C expansion card
2. Measure and cut the rear of the YubiKey 5C to fit within the card shell (confirmed via teardown photos that only NFC antennas are in the rear portion)
3. Remove the YubiKey's outer collar (described as ceramic-like material) to gain the necessary length for a secure USB-C connection
4. Solder a wire to the YubiKey's touch pad and route it to the exterior for touch activation
5. Apply electrical tape to prevent false triggers from contact with the module body

The result is a fully flush, semi-permanent YubiKey that looks like a standard expansion card⁵.

alnwlsn's YubiKey 5C Holder (January 2025)

Community member alnwlsn created a non-destructive holder for the smaller YubiKey 5C (non-NFC, non-Nano version)⁶⁷. Unlike moparisthebest's approach, this design does not require cutting the YubiKey.

Design features⁶⁷:

• The key snaps into the shell and is secured by the YubiKey's ENIG-plated "wings" (capacitive touch sensor contacts)
• A shelled wire-wrapping wire extends the capacitive touch sensor to an external M3 socket head bolt
• Based on Framework's OpenSCAD files, redrawn in FreeCAD
• STEP and FreeCAD source files provided for customization

Comparison

Feature	Ivan_Grynov	Stavros (Solo 2)	moparisthebest	alnwlsn
Key Used	YubiKey 5C	Solo 2	YubiKey 5C (cut)	YubiKey 5C (non-NFC)
Key Modified	No	No	Yes (rear cut off)	No
Touch Access	Hole underneath	Outer edge of key	External wire	External bolt
Source Files	STL1	Not published3	Not published5	STEP, FreeCAD6
Date	Sep 2022	Jan 2023	Apr 2024	Jan 2025

Compatibility

All YubiKey expansion card adapters are compatible with Framework laptops that have user-expandable expansion card slots:

• Framework Laptop 13 (all generations)
• Framework Laptop 16
• Framework Desktop

The adapters connect to the internal USB-C port exposed by removing an expansion module. They do not occupy an additional expansion card slot — they replace one.

Related Projects

• Framework ExpansionCards — Official open-source reference designs for Framework expansion card enclosures⁴
• DongleHider+ — A community expansion card that hides a USB dongle internally while providing an external USB-A port
• Yubico x Framework cooperation? — Community discussion about an official Framework/Yubico partnership

Footnotes

1. Yubikey 5C adapter — Framework Community (Ivan_Grynov, September 2022) ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Integrated YubiKey Expansion Card — Framework Community (moparisthebest, April 2024) ↩ ↩²

3. Making a security key for the Framework laptop — Stavros Korokithakis (January 2023) ↩ ↩² ↩³ ↩⁴ ↩⁵

4. FrameworkComputer/ExpansionCards — GitHub ↩ ↩²

5. Frame.work YubiKey Expansion Card — moparisthebest (April 2024) ↩ ↩² ↩³ ↩⁴ ↩⁵

6. a Yubikey holder — alnwlsn (January 2025) ↩ ↩² ↩³

7. Another Yubikey 5C adapter — Framework Community (alnwlsn, January 2025) ↩ ↩²