Default How to edit the .img file.

Hello,

I'm trying to edit .IMG file to make some changes. I have "boot.img" and I've tried to extract it using `unpackbootimg` tool with following result:

5AB9CF0431DD269C/U# unpackbootimg -i boot.img -o boot
BOARD_KERNEL_CMDLINE androidboot.hardware=qcom user_debug=31 zcache
BOARD_KERNEL_BASE 80200000
BOARD_PAGE_SIZE 2048
Segmentation fault (core dumped)


Thanks.