Summary
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LEGO MINDSTORMS EV3 is a toy robot produced by the LEGO Group. It is based
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on the davinci da850 evm. The EV3 has a 16MB spi flash and a SDHC microSD card
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reader.
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Booting
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=======
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The EV3 contains a bootloader in EEPROM that loads u-boot.bin from address 0x0
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of the spi flash memory. Using the default configuration, u-boot will check to
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see if there is a boot.scr file on the first FAT partition of the mmc. If there
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is, it will run the script and boot the kernel from the uImage file also in
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the FAT partition. Otherwise, it will load a kernel and rootfs from the flash.
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The kernel must be stored at address 0x50000 on the flash and have a maximum
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size of 3MiB. The rootfs must be a squasfs image and stored at 0x350000 in the
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flash and have a maximum size of 9.3MiB. The flash starting at 0xCB0000 is
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reserved for user data.
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Writing image to flash
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======================
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The EEPROM contains a program for uploading an image file to the flash memory.
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The program is started by holding down the right button on the EV3 when powering
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it on. You can also `run fwupdateboot` in the u-boot shell to reboot into this
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mode. The image can then be uploaded using the official LEGO MINDSTORMS EV3
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software or a 3rd party program capable of uploading a firmware file.
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If you are booting from the microSD card, it is enough to just write uboot.bin
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to the flash. If you are not using a microSD card, you will need to create an
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image file using the layout described above.
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