What is the micro:bit firmware
Firmware is a special kind of software that makes the hardware function properly. In the case of the micro:bit, the firmware enables the device to be programmed via USB.
The micro:bit has two chips on the back of it; one of them runs your code, while the other one runs the firmware that enables the micro:bit to appear on your computer as a USB drive so you can flash a program to it. There are two micro:bit versions with different firmware, so you should check whether you have the latest version before carrying out the update.
There may be times when you may want to update the firmware to test out new software features.
How to find out the current firmware version
Before you upgrade, you'll want to find out what version of the firmware you have on your micro:bit. Plug it in via USB, open up the DETAILS.TXT file fom the MICROBIT drive and look for the number on the line that begins 'Interface Version'.
# DAPLink Firmware - see https://mbed.com/daplink
Unique ID: 9900000031634e4500624014000000320000000097969901
HIC ID: 97969901
Auto Reset: 1
Automation allowed: 0
Overflow detection: 0
Daplink Mode: Interface
Interface Version: 0249
Git SHA: 682d8303e37355532402b8d93c4f240a3cec02a9
Local Mods: 0
USB Interfaces: MSD, CDC, HID, WebUSB
Interface CRC: 0x3f2b7e12
Remount count: 0
If you have the latest micro:bit V2, the Interface Version will be at least 0255
If you have the previous micro:bit the interface Version will be at most 0254
How to update the firmware
The DETAILS.TXT file on the BBC micro:bit drive may give conflicting information to the same file when opened in MAINTENANCE mode. This is fine. In our case, we are only updating the firmware for the interface chip, so you will see the changes when the BBC micro:bit is reset in normal operating mode.
This firmware package is published on the official DAPLink github repository
And you can find previous shipped firmware updates in our developer documentation https://tech.microbit.org/software/daplink-interface/#daplink-software
Kewords for search: upgrade the built-in firmware, software, hardware, maintenance