$ make pico-imx7d_defconfig
$ make
-This generates the U-Boot binary called u-boot.imx.
+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)
Open a terminal program such as minicom.
-Copy u-boot.imx to the imx_usb_loader folder.
+Copy SPL and u-boot.img to the imx_usb_loader folder.
+
+Load the SPL binary via USB:
-Load u-boot.imx via USB:
+$ sudo ./imx_usb SPL
-$ sudo ./imx_usb u-boot.imx
+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.
=> 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 into the eMMC:
+Flash SPL and u-boot.img into the eMMC running the following commands on a PC:
$ sudo dfu-util -D SPL -a spl
-Flash u-boot.img into the eMMC:
-
$ sudo dfu-util -D u-boot.img -a u-boot
Remove power from the pico board.