Difference between revisions of "NAND flash boot rootfs"
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(Created page with "===Boot from NAND flash=== * The default boot option - power on. * A UBIFS image of rootfs is written to /dev/mtd4 ('''ubi0:elphel393''' in bootargs in the device tree) ====Refla...") |
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Revision as of 10:46, 9 March 2016
Boot from NAND flash
- The default boot option - power on.
- A UBIFS image of rootfs is written to /dev/mtd4 (ubi0:elphel393 in bootargs in the device tree)
Reflash factory image (update software/firmware or corrupt flash partition)
- Use files from .../poky/build/tmp/deploy/images/elphel393/nand/
- Copy all of the image files to a micro SD card (or boot first from the card then copy over network)
- Boot from micro SD card.
- Reflash what is needed:
- Reflash SPL (boot.bin, /dev/mtd0)
cd <path-to-image-files> # boot.bin # mtd0 is 1MB (8 eraseblocks,128K = 1 block, there are 64 pages of 2048 per block) # erase only first 2 blocks, other block are reserved for copies flash_unlock /dev/mtd0 flash_erase /dev/mtd0 0 2 nandwrite -n /dev/mtd0 -p boot.bin
- Reflash u-boot (u-boot-dtb.img, /dev/mtd1)
cd <path-to-image-files> # u-boot-dtb.img # mtd1 is 4M (32 eraseblocks,128K = 1 block, there are 64 pages of 2048 per block) # erase only the 1st 8 blocks as image is <1M, leave unused area for backup copies flash_unlock /dev/mtd1 flash_erase /dev/mtd1 0 8 nandwrite -n /dev/mtd1 -p u-boot-dtb.img
- Reflash devicetree (devicetree.dtb, /dev/mtd2)
cd <path-to-image-files> # u-boot-dtb.img # mtd2 is 1M (8 eraseblocks,128K = 1 block, there are 64 pages of 2048 per block) flash_unlock /dev/mtd2 flash_erase /dev/mtd2 0 8 nandwrite -n /dev/mtd2 -p devicetree.dtb
- Reflash kernel (uImage, /dev/mtd3)
cd <path-to-image-files> # uImage # mtd3 is 16M (128 eraseblocks,128K = 1 block, there are 64 pages of 2048 per block) flash_unlock /dev/mtd3 flash_erase /dev/mtd3 0 128 nandwrite -n /dev/mtd3 -p uImage
- For rootfs there are 2 options:
- update - recommended, rootfs.ubifs
- reflash - radical, rootfs.ubi
- For rootfs there are 2 options:
Update:
# NOT TESTED ubiattach /dev/ubi_ctrl -m 4 #ubimkvol /dev/ubi0 -N elphel393-rootfs -s 256MiB ubiupdatevol /dev/ubi0_0 rootfs.ubifs # read: http://www.linux-mtd.infradead.org/faq/ubifs.html # read: http://free-electrons.com/blog/creating-flashing-ubi-ubifs-images/ # read: http://www.linux-mtd.infradead.org/doc/ubi.html#L_volupdate # read: http://comments.gmane.org/gmane.linux.drivers.mtd/39415
Reflash:
cd <path-to-image-files> flash_unlock /dev/mtd4 flash_erase /dev/mtd4 0 2048 ubiformat /dev/mtd4 -f rootfs.ubi -s 2048 -O 2048
Note: Considering to store the u-boot, device tree and kernel on UBUFS partitions in future.
