There is an automation mode feature built in to the interface chip which can be used to quickly erase the BBC micro:bit. This could be used for example, to clear a large number of micro:bits ready for another lesson or workshop. To do this:

  1. Check what version of interface firmware is installed on your micro:bit by plugging in the micro:bit via USB and browsing to the DETAILS.TXT file on the micro:bit drive.


  2. If the version is below 0241, update the firmware on the micro:bit
  3. Enable automation mode:

    a) Download the auto_on.cfg attachment and erase.act from this article

    b) hold the RESET button on the back of the micro:bit firmly

    c) at the same time as holding the RESET button, drag the auto_on.cfg file to the MICROBIT drive

    d) this will enable a new feature. Now let go of RESET and power cycle your micro:bit

    e) open DETAILS.TXT again and make sure that you see 'Automation Allowed: 1' in the file

  4.  Now download the erase.act file attached to this article and store it on your hard disk.

  5. If ever you want to quickly erase the program memory on the micro:bit, just drag erase.act onto the MICROBIT drive and it will quickly erase the whole program memory.


1) If the program memory of the micro:bit is completely empty, you will not be able to use the Bluetooth pairing mode at all. To recover the bluetooth pairing feature, please follow the instructions in this article:

2) Compass calibration data will be lost as a part of erasing the flash memory. Next time you flash a new .hex to your micro:bit, if you are using the compass, you will have to recalibrate it as described in this article:


[1] enabling automation mode in DAPLink:

[2] Erasing program flash using an MSD command:

Keywords for search: clear, memory, empty, reset, wipe