How to modify the RamDisk image that comes with release 14.5

I want to modify the RamDisk image file inside the archive 14.5-qemu-ramdisk.image.gz and include my own custom program in it. This version of RamDisk came with the latest version of linux released for zed board as downloaded from http://www.wiki.xilinx.com/Zynq+14.5+-+2013.1+Release

I tried following the instructions on http://zedboard.org/content/zedboard-modifying-your-ram-disk-image

But the command mount -o loop ramdisk.image mnt does not work for this particular RamDisk image (version 14.5). I get the error "invalid argument".

0 Former Member over 11 years ago

Strip the mkimage header...no problem
gunzip, ok...
mount -o loop ramdisk.image fails...
with "invalid arguement" ...
Any help?
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0 Former Member over 11 years ago

What you're doing is mounting the image like it's a filesystem, so you have to create a folder ("mount point") and mount the image on that folder. Here's me doing it, notice how I create the folder, mount the image on it, ls to see what's in it (here is where you would add your program), then unmount and do another ls to show the folder is empty now.

chris2@lindev:~/rd_test$ ls
ramdisk.image.gz
chris2@lindev:~/rd_test$ gunzip ramdisk.image.gz
chris2@lindev:~/rd_test$ ls
ramdisk.image
chris2@lindev:~/rd_test$ mkdir tmp_mnt
chris2@lindev:~/rd_test$ sudo mount -o loop ramdisk.image tmp_mnt
[sudo] password for chris2:
chris2@lindev:~/rd_test$ cd tmp_mnt/
chris2@lindev:~/rd_test/tmp_mnt$ ls
bin dev etc home lib linuxrc lost+found media mnt opt proc root run sbin sys tmp usr var
chris2@lindev:~/rd_test/tmp_mnt$ cd ..
chris2@lindev:~/rd_test$ sudo umount tmp_mnt
chris2@lindev:~/rd_test$ ls tmp_mnt/
chris2@lindev:~/rd_test$ gzip ramdisk.image
chris2@lindev:~/rd_test$

Then do your u-boot wrap and you should be good to go. Hope that helps.
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0 Former Member over 11 years ago

Hi,
I'm trying to do the same as farseer but i can't gunzip the uramdisk.image.gz.

******
/arm-devel/ramdisk/sdcard# gunzip uramdisk.image.gz

gzip: uramdisk.image.gz: not in gzip format
******

The file I downloaded is different as yours:
mine: uramdisk.image.gz
yours: ramdisk.image.gz

could that be the reason? how could I gunzip that file ramdisk image?

Thanks!!!
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0 Former Member over 11 years ago in reply to Former Member

hi ,
did you solve it ?
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0 Former Member over 11 years ago in reply to Former Member

In case you still need this:
That uramdisk file is wrapped with a u-boot header that you need to strip off, before feeding it into gunzip:

# dd if=./uramdisk.image.gz of=./ramdisk.image.gz skip=16 bs=4

More info here: http://www.wiki.xilinx.com/Build+and+Modify+a+Rootfs
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0 Former Member over 10 years ago

This doesn't work for me, after going from uramdisk.image.gz to ramdisk.image.gz to ramdisk.image, I cannot mount it:

$ sudo mount -o loop ramdisk.image zed
mount: you must specify the filesystem type

$ file ramdisk.image
ramdisk.image: ASCII cpio archive (SVR4 with no CRC)

$ /sbin/fdisk -l ramdisk.image
last_lba(): I don't know how to handle files with mode 81a4
Disk ramdisk.image: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk ramdisk.image doesn't contain a valid partition table
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0 Former Member over 10 years ago in reply to Former Member

Apparently I had to follow the instructions as a CPIO archive... Which they say is _not_ for the zedboard, but nevermind.
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