| How to Update U-Boot on Pico-imx6ul board |
| ----------------------------------------- |
| |
| Required software on the host PC: |
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| - imx_usb_loader: https://github.com/boundarydevices/imx_usb_loader |
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| - dfu-util: http://dfu-util.sourceforge.net/releases/ |
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| Build U-Boot for Pico: |
| |
| $ make mrproper |
| $ make pico-imx6ul_defconfig |
| $ make |
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| This generates the SPL and u-boot.img binaries. |
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| 1. Loading U-Boot via USB Serial Download Protocol |
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| 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. |
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| Put pico board in USB download mode (refer to the document |
| http://www.wandboard.org/images/hobbit/hobbitboard-imx6ul-reva1.pdf page 15) |
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| Connect a USB to serial adapter between the host PC and pico |
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| Connect a USB cable between the OTG pico port and the host PC |
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| Open a terminal program such as minicom |
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| Copy SPL and u-boot.img to the imx_usb_loader folder. |
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| Load the SPL binary via USB: |
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| $ sudo ./imx_usb SPL |
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| Load the u-boot.img binary via USB: |
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| $ sudo ./imx_usb u-boot.img |
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| Then U-Boot should start and its messages will appear in the console program. |
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| Use the default environment variables: |
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| => env default -f -a |
| => saveenv |
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| 2. Flashing U-Boot into the eMMC |
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| Run the DFU command: |
| => dfu 0 mmc 0 |
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| Flash SPL and u-boot.img into the eMMC running the following commands on a PC: |
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| $ sudo dfu-util -D SPL -a spl |
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| $ sudo dfu-util -D u-boot.img -a u-boot |
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| Then on the U-Boot prompt the following message should be seen after a |
| successful upgrade: |
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| #DOWNLOAD ... OK |
| Ctrl+C to exit ... |
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| Remove power from the pico board. |
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| Put pico board into normal boot mode |
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| Power up the board and the new updated U-Boot should boot from eMMC. |