13 Nano Debugger Firmware

13.1 Firmware Packs

The Nano Debugger firmware is not open source. Intel HEX files are included in the Tool Packs published by Microchip on the Microchip Packs Repository under PKOB nano support.

Inside each Tool Pack, you will find a firmware subfolder containing nedbg_fw.zip. The file avrtools_fw.xml provides information about the HEX file nedbg.hex.

Standalone Upgrade

Use pydebuggerupgrade to update the firmware on your Nano Debugger.

Tip: use the command

pydebuggerupgrade latest

to automatically get the latest released firmware

Tip: use the command

pydebuggerupgrade <x.y.z>

to automatically download and install the firmware in pack version x.y.z

IDE Upgrade

Use the Pack Manager in MPLAB X and MPLAB Tools for VS Code to download the latest Nano Debugger firmware pack. The firmware is updated automatically when the IDE connects to the kit.

Note: Be sure to select either a specific Tool Pack or "latest" in the project properties.

Legacy Upgraders

Microchip Studio only includes bundled firmware, which is no longer updated. Use a standalone upgrader or atfw.exe to update the firmware on the Nano Debugger.

Note: Microchip Studio may automatically downgrade your Nano Debugger to the latest bundled firmware. To prevent this behavior, delete or rename the firmware zip file inside the Microchip Studio Program Files folder.

Use the atfw.exe from Microchip Studio:

Tip: use the command

atfw.exe -a <zipfile>

to upgrade the firmware using a zip archive extracted from a Tool Pack

13.2 Revision History

Note: The revision is specified in decimal in this table, but some IDEs and tools report it in hexadecimal.

Table 13-1. Revision history of the Nano Debugger firmware
Revision	Tool Pack	Release date	Reference	Notable fixes and features
1.34	1.18.x	December 2025	FW5G-1580	SWD timing improvements
1.33	1.17.969	September 2025	FW5G-1459	dsPIC33A support and fixes DAP_SWJ_Pins timing fix
1.32	1.16.876	March 2025	FW5G-1362	AVR-SD UPDI handshake
1.31	1.14.751	April 2024	FW5G-1323	added UF2 parser
1.30	1.13.715	October 2023	FW5G-1306	hotfix for previous 1.29 hex file issue
1.29	1.12.711	October 2023	FW5G-1250	fix for AVR NVM P:4 added support for AVR BOOTROW added PDID protection filter
1.27	1.11.554	December 2022	FW5G-1192	added AVR NVM P:4 added support for dsPIC33
1.25	1.10.488	May 2022	FW5G-1133	added support for CDC BREAK
1.23	1.9.446	December 2021	FW5G-1086	added AVR EA support fix to AVR fuse protection
1.22	1.7.295	March 2021	FW5G-880	multiple CDC fixes
1.21	1.5.210	September 2020	FW5G-744	added MSC to CDC bridge
1.20	1.3.164	June 2020	FW5G-708	SAM-IoT related fixes
1.17		March 2020	FW5G-620	added SAM-IoT
1.16	1.0.33	March 2020	FW5G-516	Initial public tool pack release
pre 1.16	-	2018-2019	FW5G-485	Internal releases and bundles with Studio/MPLAB

Tip: The reference can be used when contacting Microchip support