currently i see, unpacked boot.img extract uncompressed kernel with name "Kernel" but that files did not contain appended dtb files
in example mkdtimg support that
mkbootimg --kernel Image.gz-dtb --ramdisk \
out/target/product/pixel3_mainline/ramdisk.img \
--base 0x00000000 --pagesize 4096 \
--cmdline "" --output boot.img
Can it be used in Android_boot image editor ?