---
name: "uflash"
section: "1"
platform: "linux"
package: "python3-uflash"
version: "1.2.4+dfsg-10"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/uflash"
---

# uflash(1)

utility for flashing the BBC micro:bit with Python scripts and the MicroPython runtime

## NAME

**uflash** - utility for flashing the BBC micro:bit with Python scripts and the MicroPython runtime

## SYNOPSIS

**uflash** \[**--runtime** *RUNTIME*\] \[**--watch**\] \[**--minify**\] \[*source*\] \[*target* \[*target...*\]\]

**uflash** **--extract** *HEXFILE* \[*source*\]

**uflash** **--version**

**uflash** **--help**

## DESCRIPTION

**uflash** flashes Python onto a BBC micro:bit or extracts Python source from a .hex file. If no path to the micro:bit is provided, **uflash** will attempt to autodetect the correct path to the device. If no path to the Python script is provided, **uflash** will flash an unmodified MicroPython firmware onto the device.

## OPTIONS

uflash supports the following options:

- \-r, --runtime *RUNTIME*

  use the specified MicroPython runtime file

- \-w, --watch

  watch the source file for changes

- \-m, --minify

  minify the source

- \-e, --extract *HEXFILE*

  extract Python source from given hex file

- *source*

  the Python source file to flash or extract to

- *target*

  path to one or more mounted micro:bit devices

- \-h, --help

  display usage information and exit

- \--version

  display current version and exit

## EXAMPLES

If you type the command on its own then **uflash** will attempt to find a connected BBC micro:bit and flash an unmodified default version of the MicroPython runtime onto it:

-

  ```
  $ uflash
  Flashing Python to: /media/ntoll/MICROBIT/micropython.hex
  ```

To flash a version of the MicroPython runtime with a specified script embedded within it (so that script is run when the BBC micro:bit boots up) then pass the path to the Python script in as the first argument to the command:

-

  ```
  $ uflash my_script.py
  Flashing Python to: /media/ntoll/MICROBIT/micropython.hex
  ```

You can let **uflash** watch for changes of your script. It will be flashed automatically every time you save it:

-

  ```
  $ uflash --watch my_script.py
  ```

At this point **uflash** will try to automatically detect the path to the device. However, if you have several devices plugged in and/or know what the path on the filesystem to the BBC micro:bit already is, you can specify this as a second argument to the command:

-

  ```
  $ uflash myscript.py /media/ntoll/MICROBIT
  Flashing Python to: /media/ntoll/MICROBIT/micropython.hex
  ```

You can even flash multiple devices at once:

-

  ```
  $ uflash myscript.py /media/ntoll/MICROBIT /media/ntoll/MICROBIT1
  Flashing Python to: /media/ntoll/MICROBIT/micropython.hex
  Flashing Python to: /media/ntoll/MICROBIT1/micropython.hex
  ```

To extract a Python script from a hex file use the “–extract” flag like this:

-

  ```
  $ uflash --extract something.hex myscript.py
  ```

This will save the Python script recovered from “something.hex” into the file “myscript.py”. If you don’t supply a target the recovered script will emit to STDOUT.

If you’re developing MicroPython and have a custom runtime hex file you can specify that **uflash** use it instead of the default version of MicroPython in the following way:

-

  ```
  $ uflash --runtime=firmware.hex
  ```

## FILES

The default MicroPython firmware file is located in /usr/share/firmware-microbit-micropython/firmware.hex.

## REPORTING BUGS

Upstream bug tracker: https://github.com/ntoll/uflash/issues

## COPYRIGHT

Copyright 2015-2018 Nicholas H.Tollervey and others.

## AUTHOR

This manual page is based on the uflash documentation. It was created by Nick Morrott \<nickm@debian.org\> for the Debian GNU/Linux system, but may be used by others

## SEE ALSO

[**mu-editor**(1)](/mu-editor/1.md)

https://uflash.readthedocs.io/en/latest/