Bus Pirate: Bootloader v4.3/v4.4 upgrade

See the latest version in the documentation wiki.

Bus Pirate developers have been using an updated v4 bootloader for several months. It’s tested really well, so we packaged it in an installer.

Bootloader v4.3/v4.4 is a minor update of v4.1/4.2. It is not a required update. Any v4+ firmware will work with any v4+ bootloader. The upgrade should only be used with an existing v4 bootloader, if you still have v2 bootloader (with P24QP.exe) please upgrade to v4.1 first before upgrading to v4.3.

The new bootloader has these improvements:

  • Proper timeout – if you enter with a jumper you can remove it to go back to the firmware with re-plugging the USB cable. (does not work when you jump from the terminal with $).
  • Supports multiple connects – you can now press the check bootloader button, then download, without having to replug the Bus Pirate.
  • If the bootloader is active and you type into the terminal, the bootloader will display ‘BL4+’ so you know the Bus Pirate is functioning and in bootloader mode, not dead.

Download the upgrade package. Upgrade help is available here.

Bootloader v4.3 is the version of the v4.3/v4.4 bootloader installed with an upgrader. It is the same as v4.4 in the regular firmware releases, but v4.4 is programmed with a PIC programmer like a PICkit2 or ICD2. Sorry, no bootloader upgrader utility is available for Bus Pirate v1a. We did compile an updated bootloader for the v1a, but you’ll need to download it in the latest project archive and program it with a PIC programmer

What you’ll need:

  • Bus Pirate (v2go or v3) with a v4+ bootloader installed
  • ds30 Loader or pirate-loader upgrade application
  • Bootloader updater (BPv3-bootloader-upgrade-v4xtov4.3.hex)
  • v4+ firmware (BPv3-Firmware-v5.0.hex)

The upgrade package contains all the required files.


We’re going to:

  • Connect to the Bus Pirate bootloader and upload the updater .HEX
  • Open a serial terminal and run the updater (type yes to confirm)
  • Connect to the new bootloader and upload a Bus Pirate firmware .HEX

Step 1. Upload the updater

Follow the ds30 Loader or pirate-loader instructions to load BPv3-bootloader-upgrade-v4xtov4.3.hex. This usually involves entering the bootloader with a jumper or by typing $ into the terminal, then loading the file with your preferred application.

Step 2. Run the updater

The program we just put in the Bus Pirate will install the updated bootloader, but it has to be executed from a serial terminal.

Open a terminal to the Bus Pirate’s serial port and press space for further instructions. The screen will display your current bootloader version and the version that will be installed. If everything looks right then type ‘yes’. The upgrade will be installed in just a fraction of a second.

At the end of the upgrade the Bus Pirate will go north jump straight into the new bootloader. Just close the terminal without typing anything. You should be able to move to the next step without attaching a jumper to reenter the bootloader.

Step 3. Upload a Bus Pirate firmware

Now repeat the ds30 Loader or pirate-loader instructions to load a v4+ firmware, such as the recent v5.0 release (BPv3-Firmware-v5.0.hex included in this update).

Unplug the Bus Pirate, plug it in again. Open a serial terminal to the Bus Pirate and press i, the info should display the bootloader version as v4.3.

v4.3 is the version of the v4.3/v4.4 bootloader installed with an upgrader. It is the same as v4.4 in the project archive, but v4.4 is programmed with a PIC programmer like a PICkit2 or ICD2.

Join the Conversation


  1. Hi,

    I’ve just upgraded my BP from (Bus Pirate V3 Firmware V3) to (Bus Pirate v3 Firmware v5.0 (r382) Bootloader v4.3) without a SINGLE problem in about 10 minutes.

    I just followed instructions thoroughly and it worked like a charm :)

    I big thank you to providers and to early testers of upgrades for ironing out the process for all of us.

    You guys rock !

  2. Just wanted to make sure if I didn’t miss the memo…. Bootloader 4.3/4.3 is for Bus Pirate v3 only? (Not applicable for V2go, right?)

  3. yay, worked flawlessly! It took me a bit of time to figure out that 4.4 was NOT to be used with ds30/pirate-loader, but after finding this post it became obvious why.. :)


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