[Buildroot] genimage raw partition from multiple files
Michał Łyszczek
michal.lyszczek at gmail.com
Wed Aug 2 17:25:02 UTC 2017
W dniu 02.08.2017 o 15:55, Michał Łyszczek pisze:
> Hi,
>
> I've been trying to figure out, how to create raw partition, without
> filesystem, from 2 or more files. Here is a general idea
>
>
> partition uboot {
> partition-type = 0xa2
> size = 1M
>
> image spl {
> image = "u-boot-spl.bin.crc"
> size = 64k
> offset = 0
> }
>
> image uboot-real {
> image = "u-boot.bin"
> offset = 256k
> }
> }
>
>
> Note that spl is 64k big, and uboot-real must be at offset 256k. Also
> this *MUST* be a partition of type 0xa2. Can such thing be done fully in
> genimage without post-install script?
>
Ok, after messing with source code a little bit a found a way to do what
I want. Let's say want to create partition of type 0xA2 for uboot. That
partition should contain spl image and full uboot. First create image of
that partition - this image will be built from "subpartitions"
image uboot.img {
hdimage {
partition-table = "no"
}
partition spl {
in-partition-table = "no"
image = "u-boot-spl.bin.crc"
offset = 0
size = 64k
}
partition uboot-full {
in-partition-table = "no"
image = "u-boot.img"
offset = 256k
}
size = 1M
}
2 things are very important here, first is "partition-table = "no"" in
hdimage, this will tell hdimage not add ANYTHING from itself, so no
partition table, no dos magic (55 aa), no mbr at all. All partitions
should also have "in-partition-table = "no"" to prevent any additional
bytes from genimage.
When image is created like that it can be normally added into partition
table
image sdcard.img {
hdimage {
}
partition uboot-env {
in-partition-table = "no"
image = "uboot-env.bin"
offset = 17408 # 512 * 34 -> just after gpt
}
partition uboot {
partition-type = 0xa2
image = "uboot.img"
}
partition rootfs {
partition-type = 0x83
image = "rootfs.ext2"
size = 500M
}
}
And that's all, image will generate as expected. This may look like
hack, but it is quite clean solution I think. We can avoid any scripts
to create such partition for bootloader, and everything is in one place.
--
Best Regards
Łyszczek Michał
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