How to Update U-Boot on Pico-imx6ul board
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Required software on the host PC:
- imx_usb_loader: https://github.com/boundarydevices/imx_usb_loader
- dfu-util: http://dfu-util.sourceforge.net/releases/
Build U-Boot for Pico:
$ make mrproper
$ make pico-imx6ul_defconfig
$ make
This will generate the U-Boot binary called u-boot.imx.
Put pico board in USB download mode (refer to the document
http://www.wandboard.org/images/hobbit/hobbitboard-imx6ul-reva1.pdf page 15)
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 u-boot.imx to the imx_usb_loader folder.
Load u-boot.imx via USB:
$ sudo ./imx_usb u-boot.imx
Then U-Boot should start and its messages will appear in the console program.
Use the default environment variables:
=> env default -f -a
=> saveenv
Run the DFU command:
=> dfu 0 mmc 0
Transfer u-boot.imx that will be flashed into the eMMC:
$ sudo dfu-util -D u-boot.imx -a boot
Then on the U-Boot prompt the following message should be seen after a
successful upgrade:
#DOWNLOAD ... OK
Ctrl+C to exit ...
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.
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