How to obtain Image from zImage?

Ho0ligaN · 08-06-2010, 12:44 AM

Hi,
I have obtained zImage from uImage by using this script http://buffalo.nas-central.org/wiki/...ract_an_uImage

Then I used the zlib library from www.zlib.net and the accompanying zpipe.c file to uncompress zImage but I am getting this error

zpipe: invalid or incomplete deflate data

Am I on the right path? My aim is to obtain completely uncompressed Image.

EDIT: The kernel is 2.6.29

estabroo · 08-06-2010, 07:46 AM

zimage is a self extracting gzip compressed image, you might be able to decompress it by finding the starting offset of the data in the file

estabroo · 08-06-2010, 08:25 AM

http://openinkpot.org/wiki/Documentation/ZImageFormat

This has the info you need

Ho0ligaN · 08-09-2010, 04:43 AM

Hey thanks for the link. I followed that method as follows

Code:

$ arm-linux-objdump -EL -b binary -D -m armv5t zImage | grep 8b1f
    39e0:	088b1f00 	stmeq	fp, {r8, r9, sl, fp, ip}
   11a60:	c8b1f58e 	ldmgt	r1!, {r1, r2, r3, r7, r8, sl, ip, sp, lr, pc}

Then obtained piggy.gz

Code:

$ dd if=zImage of=piggy.gz bs=1 skip=14816

Now, when I try gunzipping piggy.gz it still says its not in gunzip format

Code:

$ gunzip piggy.gz

gzip: piggy.gz: not in gzip format

any solutions?

Ho0ligaN · 08-10-2010, 04:18 AM

Bump!

estabroo · 08-10-2010, 06:41 AM

Are you sure you wanted little-endian? ARM can be either.

Ho0ligaN · 08-10-2010, 07:10 AM

I tried both, but to no avail

This is for android BTW, but I think it should work for all zImages?

Ho0ligaN · 08-10-2010, 08:13 AM

Code:

dd if=zImage of=piggy.gz bs=1 skip=14817

That did the trick!

Jon Shemitz · 11-30-2010, 06:04 PM

openinkpot.org/wiki/Documentation/ZImageFormat refers to armeb-linux-gnu-objdump.zz. I don't have that executable, so I just used

hexdump zImage |grep -E "8b ?1f"

and it worked just fine.

willem640 · 07-15-2017, 04:29 AM

your piggy can also be in xz format. have you tried executing file?

edit:
i mean the built in file command with the magic files

NevemTeve · 07-15-2017, 07:47 AM

zImage is a compressed format of Linux kernel, not an actual image.

jefro · 07-15-2017, 08:30 PM

Hello and welcome to LQ, willem640.

We usually try to avoid posting to very old threads. They tend to have out of date information. If you can advance some old threads then OK otherwise we have many current questions that need assistance.