⭕Yubikey Firmware

Can you upgrade the firmware on your Yubikey? This section explains what firmware is, and what to do when your Yubikey becomes outdated.

The latest firmware version as of January 31, 2023 (first seen in July 2021) is:

v5.4.3

❊ What Is Firmware?

Firmware is a specific class of computer software which provides low-level control for a device's specific hardware. Typically firmware is stored on EEPROM (electrically erasable programmable read-only memory), and is a type of non-volatile memory used in computers or computer related devices.

To get an idea of what makes up a Yubikey, a few of the known controller chips used to manufacturer Yubikeys have been provided below. These controller chips may vary depending on the type of Yubikey you've purchased, but it gives an idea as to what makes a Yubikey work.

Controller Chip

EEPROM / Flash

Device

NXP A7005

76 kB

Yubikey 4

NXP LPC11U24FHI33/CP3303

4 kB / 32kB

Yubikey 4

Infineon SLE 78CLUFX5000P01

*< 500 kB

Yubikey 5

Fun Fact:

Current estimates on parts to make a Yubikey puts the manufacturing cost at roughly $5 - 6.00 USD.

*Note: Datasheets on the Infineon MCU for Yubikey 5 are very minimal. Info claims that the chip simply has 500kB of non-volatile memory and 16kB RAM (volatile). Yubikey 4 -> Yubikey 5 models went from a two controller chip setup to a single controller chip and switched chip manufacturers.

❊ Yubikey Firmware

The firmware in a Yubikey is included with the device itself, and is physically stored as programming within the EEPROM (or ROM -- ready-only memory). This firmware determines what features your Yubikey has and what it supports. Firmware is released by Yubico, which provides security improvements, as well as support for new features.

For an idea of how often firmware is released, firmware v5.4 was released in May of 2021 with reports of v5.4.3 releasing to the public in July of 2021.

❊ Upgrading Firmware

The Yubikey itself contains non-upgradable firmware. This means that whatever firmware the Yubikey shipped with when you made your order, is the firmware you will keep. The reason for non-upgradable firmware is to prevent attacks on the YubiKey which might compromise its security.

❊ Newer Firmware

Due to the fact that a Yubikey's firmware is non-upgradable, if you see a press release announcing a new version of the firmware being released with a particular feature that you want, you will need to purchase a new Yubikey.

To ensure that you get the latest firmware, during the process of placing your order; you may include an order note with something similar to the following: