Update firmware using the UF2 Bootloader¶

Overview¶

iMX RT1011 Nano Kit is shipped with the UF2 Bootloader, which is an easy-to-use and self-upgradable bootloader that can be used to update the firmware by just copying the .uf2-format images to the flash drive without using an external programmer.

UF2 Bootloader runs entirely on SRAM which is not only super fast but also easy to perform self-update. After powering on, if UF2 Bootloader already exists on external flash, it will be loaded to internal SRAM and start executing from there.

This section details how to update firmware using the UF2 Bootloader.

External flash memory layout¶

When updating firmware using the UF2 Bootloader, you must be aware of where in the external flash memory the bootloader and the application firmware are located.

The following figure shows the default external flash memory layout of iMX RT1011 Nano Kit:

Installing UF2 Bootloader¶

The i.MX RT has built-in bootloader in ROM that implements the NXP Serial Download Protocol (SDP), which can be used to load & execute UF2 Bootloader to SRAM with spdhost tool via USB.

To install the UF2 Bootloader, complete the following steps:

1. Follow the SPSDK Installation Guide to install NXP SPSDK.

2. Verify the spdhost tool by running the following command:

   1	spdhost --version

3. Push and hold the USR/BT button and plug your board into the USB port of your computer.

4. A new USB device named SE Blank RT Family will be detected by your computer.
5. Download the lastest UF2 Bootloader firmware. The bootloader is located in firmware/uf2_bootloader with the name uf2_bootloader-imxrt1011_nanokit-<version>.bin.

6. Open up a terminal window and run two commands with sdphost, changing the name of the .bin file as appropriate:

   1	sdphost -u 0x1fc9,0x0145 write-file 0x20206400 uf2_bootloader-imxrt1011_nanokit-<version>.bin

   2	sdphost -u 0x1fc9,0x0145 jump-address 0x20207000

7. Re-plug the board or press the RST button, the UF2 bootloader will start running and the board will mount as a Mass Storage Device called UF2BOOT.

   

Updating the UF2 Bootloader¶

The UF2 Bootloader is self-upgradable, and you can simply drag & drop an update file in .uf2 format into UF2BOOT to update. This way is quite easy and highly recommended when updating the UF2 Bootloader to newer version.

To update the bootloader, complete the following steps:

1. Plug your board into the USB port of your computer.
2. Double-click the RST button to enter UF2 Bootloader mode.
3. The board will mount as a Mass Storage Device called UF2BOOT and the Red LED blinks slow.

4. Open INFO_UF2.TXT in the UF2BOOT volume with a text editor, and check the current version of bootloader. The figure below shows we are running the 0.18.2 version.

5. Check if newer updates are available in the firmware/uf2_bootloader folder. The update file is released with the name update-uf2_bootloader-imxrt1011_nanokit-<version>.uf2.

6. Drag and drop the update file into the UF2BOOT volume.
7. Re-plug the board and enter UF2 Bootloader mode again, then verify the version printed in INFO_UF2.TXT.

Flashing application firmware¶

It is quite easy to flash the application firmware, just simply dragging & dropping any compatible UF2 file onto the UF2BOOT volume.

To flash your application firmware, just follow the steps below:

1. Plug your board into the USB port of your computer.
2. Double-click the RST button to enter UF2 Bootloader mode.
3. The board will mount as a Mass Storage Device called UF2BOOT and the Red LED blinks slow.
4. Drag and drop the UF2 file onto the UF2BOOT volume. The RGB LED blinks red fast during flashing.
5. Re-plug or click RST button to reset the board, then the new application firmware will start running.

Generating UF2 file from .hex or .bin¶

Before flashing the .hex or .bin firmware, you need to generate them to .uf2 format. The following steps show you how to generate UF2 file from .hex or .bin file:

1. Make sure that you have Python 3.6.0 or later installed.

2. Install UF2 Converter. Open up a terminal and run the following command to install the latest prerelease version from the HEAD of the main branch:

   WindowsLinux/macOS

   1	py -3 -m pip install --pre -U git+https://github.com/makerdiary/uf2utils.git@main

   1	python3 -m pip install --pre -U git+https://github.com/makerdiary/uf2utils.git@main

3. Verify the uf2conv tool by running the following command:

   1	uf2conv --help

4. To generate UF2 file, simply use uf2conv on a .hex or .bin file, specifying the family as 0x4fb2d5bd:

   Generating from .hexGenerating from .bin

   1	uf2conv -f 0x4fb2d5bd -c -o application.uf2 application.hex

   1	uf2conv -f 0x4fb2d5bd -c -b 0x6000C000 -o application.uf2 application.bin