USB/DFU

AM62x USB peripheral boot (also called device boot) mode receives a second bootloader image from a USB host using the Device Firmware Update (DFU) specification defined by USB-DFU.

This section demonstrates how to use DFU to boot phyCORE-AM62x to a U-Boot prompt using a Linux Ubuntu PC.

Requirements

Hardware

  • Ubuntu 24.04 LTS or newer

    • If using a virtual machine, VMWare Workstation, VMWare Player, and VirtualBox are all viable solutions.

  • USB-C to USB-A cable

phyBOARD-AM62x USB-C Connector

Software

Prepare the following U-Boot images by building the BSP (Build the BSP) or downloading the pre-built (Pre-Built Binaries) image files. These images will be used for downloading to and booting on the phyCORE-AM62x via USB/DFU:

* tiboot3.bin-usbdfu
* tispl.bin
* u-boot.img

Note

tiboot3.bin-usbdfu is built along side tiboot3.bin and is used for USB-DFU boot on the phyCORE-AM62x.

Install & Configure Snagboot

  • Install python3, pip, and swig:

    sh-host:~$ sudo apt update && sudo apt install python3 python3-pip python3-venv swig

  • Now we can create and source our python virtual environment in the same folder that we have our U-Boot images.

    sh-host:~$ python3 -m venv myenv
sh-host:~$ source myenv/bin/activate

  • Install snagboot in our venv using pip

    sh-host:~$ pip install snagboot

  • Export the PHYTEC template

    sh-host:~$ snagrecover -t |usb-board-name| > |usb-board-name|.yaml

We can cat the template to verify it is exported correctly:

sh-host:~$ cat |usb-board-name|.yaml
tiboot3:
  path: tiboot3.bin-usbdfu
tispl:
  path: tispl.bin
u-boot:
  path: u-boot.img

  • Add udev rules to allow snagrecover to access our USB devices:

    sh-host:~$ snagrecover --udev > 50-snagboot.rules
sh-host:~$ sudo cp 50-snagboot.rules /etc/udev/rules.d/
sh-host:~$ sudo udevadm control --reload-rules
sh-host:~$ sudo udevadm trigger

Note

If we run ls our folder should include at least the following files to begin recovery:

sh-host:~$ ls
|usb-board-name|.yaml
myenv
tiboot3.bin-usbdfu
tispl.bin
u-boot.img

Booting from USB/DFU

Here are the basic steps for booting from USB/DFU on the phyCORE-AM62x development kit. The steps for establishing a serial communication are outlined in the Quickstart.

Note

Two terminals should be open on your host Linux machine.

  • One for running commands via USB-C

  • One for Serial communication to see the SOMs boot status.

Boot Switch Settings

  • S7 should be ON to override default boot settings.

USB/DFU Boot Switch phyBOARD-AM62x Boot Switches

Note

Be mindful of the switch orientation!

Prepare the Development Kit

  • Plug a USB-C cable from the phyCORE-AM62x development kit into your Ubuntu machine.

  • Power on the phyCORE-AM62x development kit.

You should see the kit appear on your Ubuntu machine via the USB-C. To verify this, run the following:

sh-host:~$ lsusb | grep 0451:6165

Bus 005 Device 060: ID 0451:6165 Texas Instruments, Inc. AM62x DFU

Loading the Bootloader Binaries

We can now begin our recovery by running snagrecover on our Ubuntu machine in our USB-C terminal.

sh-host:~$ snagrecover -s am625 -f am62x-phyboard-lyra.yaml

Starting recovery of am625 board
Installing firmware tiboot3
Searching for partition id...
Downloading file...
Could not read status after end of manifest phase
Done
Done installing firmware tiboot3
Installing firmware u-boot
Searching for partition id...
Downloading file...
Done
Done installing firmware u-boot
Installing firmware tispl
Searching for partition id...
Downloading file...
Done
Sending detach command...
Done installing firmware tispl
Done recovering am625 board

We should see the following response on our serial terminal:

Target (Serial)
U-Boot SPL 2024.04-ti-ge20920b7fc3d (Aug 20 2024 - 12:39:00 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000a '10.0.8--v10.00.08 (Fiery Fox)')
SPL initial stack usage: 13392 bytes
Trying to boot from DFU
dwc3-am62 dwc3-usb@f900000: unable to get ti,syscon-phy-pll-refclk regmap
#################################################DOWNLOAD ... OK
Ctrl+C to exit ...
############################################DOWNLOAD ... OK
Ctrl+C to exit ...
Authentication passed
Authentication passed
Authentication passed
Loading Environment from nowhere... OK
init_env from device 10 not supported!
Authentication passed
Authentication passed
Starting ATF on ARM64 core...

NOTICE:  BL31: v2.10.0(release):v2.10.0-367-g00f1ec6b87-dirty
NOTICE:  BL31: Built : 16:09:05, Feb  9 2024

U-Boot SPL 2024.04-ti-ge20920b7fc3d (Aug 20 2024 - 12:39:00 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000a '10.0.8--v10.00.08 (Fiery Fox)')
SPL initial stack usage: 1904 bytes
Trying to boot from DFU
dwc3-am62 dwc3-usb@f900000: unable to get ti,syscon-phy-pll-refclk regmap
####DOWNLOAD ... OK
Ctrl+C to exit ...
Authentication passed
Authentication passed


U-Boot 2024.04-ti-ge20920b7fc3d (Aug 20 2024 - 12:39:00 +0000)

SoC:   AM62X SR1.0 HS-FS
Model: PHYTEC phyBOARD-Lyra AM625
DRAM:  2 GiB
Core:  70 devices, 28 uclasses, devicetree: separate
MMC:   mmc@fa10000: 0, mmc@fa00000: 1
Loading Environment from nowhere... OK
In:    serial@2800000
Out:   serial@2800000
Err:   serial@2800000
Net:   eth0: ethernet@8000000port@1
Hit any key to stop autoboot:  0
=>

We should see U-Boot start up and attempt to boot Linux from the SD-Card. We can stop in U-Boot by pressing any key at this point.