Unpack U-boot.img

[ymkyu]

Hello, CreatorDev.

I succeeded build U-boot-pistachio_marduk-[version].img file. And i tried to unpack U-boot.img and extract data file. BINWALK result was "CRC32 table + LZO Compressed data", it was wrong.
I found the U-boot image build process.

u-boot-pistachio-nor.img: u-boot-dtb.img u-boot-spl-pistachio.bimg FORCE
@dd if=/dev/zero of=$@ bs=4K count=384 conv=notrunc
@dd if=u-boot-spl-pistachio.bimg of=$@ bs=4K count=128 conv=notrunc
@dd if=u-boot-dtb.img of=$@ bs=4K count=256 seek=128 conv=notrunc

BIMG image file created by bimgtool made by Imagination Technologies.

u-boot-spl-pistachio.bimg: u-boot-spl-dtb.bin FORCE
tools/bimgtool $< $@ $(CONFIG_SYS_GRAM_BASE)
CONFIG_SYS_GRAM_BASE is used as base-address in bimgtool. CONFIG_SYS_GRAM is 0x9A000000.
I don't know what it mean.

I tried to reverse engineering u-boot-pistachio_marduk-2015.10-v1.0.4.img via IDA. I took a few days to find BASE_ADDRESS, but i couldn't. I analyzed all of li(link immediate)operand and BSS initialize section to tried to found BASE_ADDRESS. But i couldn't