Program images using Fastboot

Fastboot is a protocol for communication between your device and a computer. It allows you to modify file system images over a USB connection, which is a quick way to update firmware during development. Fastboot requires the USB interface to work as 'device'.

Although it was originally developed for Android images, its implementation on the NXP UUU (Universal Update Utility) tool extends the functionality to any file type.

To update U-Boot via USB OTG using uuu and the Fastboot protocol:

Download the latest Universal Update Utility (UUU), a software tool from NXP.

UUU version should be 1.5.11 or higher.
Place the uuu executable in a directory in your PATH, such as /usr/bin.

Install udev rules to allow any user to run uuu to access the USB port:

$ sudo sh -c "uuu -udev >> /etc/udev/rules.d/70-uuu.rules"
$ sudo udevadm control --reload

Connect a micro USB cable to your development PC and the other end to the target USB OTG connector.

Reset the device by pressing the reset button on the board and immediately press any key in the serial terminal to stop the auto-boot process. The U-Boot bootloader prompt displays:

NOTICE:  CPU: STM32MP157CAC Rev.Z
NOTICE:  Model: Digi International ConnectCore MP15 Development Kit
NOTICE:  BL2: v2.6-stm32mp1-r2.1(release):dub-2021.10-r4.2(8fdd4435)
NOTICE:  BL2: Built : 14:41:33, Sep 14 2023
NOTICE:  BL2: Booting BL32
optee optee: OP-TEE: revision 3.16 (43350dda)


U-Boot dub-2021.10-r4.2 (Sep 14 2023 - 14:40:08 +0000)

CPU: STM32MP157CAC Rev.Z
DRAM:  512 MiB
optee optee: OP-TEE: revision 3.16 (43350dda)
Clocks:
- MPU : 650 MHz
- MCU : 208.878 MHz
- AXI : 266.500 MHz
- PER : 24 MHz
- DDR : 533 MHz
WDT:   Started with servicing (32s timeout)
NAND:  512 MiB
MMC:   STM32 SD/MMC: 1
In:    serial
Out:   serial
Err:   serial
Model: Digi International ConnectCore MP15 Development Kit
ConnectCore MP15 SOM variant 0x01: 512 MiB DDR3, Wi-Fi, Bluetooth
  Board version 1
Boot:  NAND
Net:   eth0: ethernet@5800a000
Normal Boot
Hit any key to stop autoboot:  0
=>

Information in the console log may vary.

On the target, in U-Boot, execute the following command:
```
=> fastboot 0
```
On your development PC, change to your Digi Embedded Yocto project’s deploy images folder:
```
$ cd tmp/deploy/images/ccmp15-dvk/
```

Run the install_linux_fw_uuu.sh script with -h parameter to check the syntax:

$ ./install_linux_fw_uuu.sh -h
############################################################
#           Linux firmware install through USB OTG         #
############################################################
Usage: ./install_linux_fw_uuu.sh [options]

  Options:
   -a <atf-filename>      Arm-trusted-firmware filename.
                          Auto-determined by variant if not provided.
   -b                     Activate bootcount mechanism (3 boot attempts).
   -d                     Install firmware on dualboot partitions (system A and system B).
                          (Implies -b).
   -f <fip-filename>      FIP filename.
                          Auto-determined by variant if not provided.
   -h                     Show this help.
   -i <dey-image-name>    Image name that prefixes the image filenames, such as 'dey-image-qt',
                          'dey-image-webkit', 'core-image-base'...
                          Defaults to 'dey-image-webkit' if not provided.
   -n                     No wait. Skips 10 seconds delay to stop script.

To program the default image files (dey-image-webkit):

$ ./install_linux_fw_uuu.sh

If your SOM has a U-Boot v2021.10-r3 or older, the install process programs the new U-Boot but fails immediately after booting it. This is due to the reworked NAND partition layout on U-Boots newer than v2021.10-r3. Press Ctrl+C on your host to cancel the script, run fastboot 0 again on the target, and retry.

For more information, check Storage layout

Once the firmware is installed, the device boots automatically. The default username is root with no password.