How to update U-Boot on pico-imx7d board
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Required software on the host PC:
- imx_usb_loader: https://github.com/boundarydevices/imx_usb_loader
Build U-Boot for pico:
$ make mrproper
$ make pico-imx7d_defconfig
$ make
This generates the SPL and u-boot.img binaries.
1. Loading U-Boot via USB Serial Download Protocol
Note: This method is convenient for development purposes.
If the eMMC has already a U-Boot flashed with DFU support then
the user can go to step 2 below in order to update U-Boot.
Put pico board in USB download mode (refer to the PICO-iMX7D Quick Start Guide
page 3)
Connect a USB to serial adapter between the host PC and pico.
Connect a USB cable between the OTG pico port and the host PC.
Open a terminal program such as minicom.
Copy SPL and u-boot.img to the imx_usb_loader folder.
Load the SPL binary via USB:
$ sudo ./imx_usb SPL
Load the u-boot.img binary via USB:
$ sudo ./imx_usb u-boot.img
Then U-Boot starts and its messages appear in the console program.
Use the default environment variables:
=> env default -f -a
=> saveenv
2. Flashing U-Boot into the eMMC
Run the DFU agent so we can flash the new images using dfu-util tool:
=> dfu 0 mmc 0
Flash SPL and u-boot.img into the eMMC running the following commands on a PC:
$ sudo dfu-util -D SPL -a spl
$ sudo dfu-util -D u-boot.img -a u-boot
Remove power from the pico board.
Put pico board into normal boot mode.
Power up the board and the new updated U-Boot should boot from eMMC.
