If you just want the image and instructions on how to fix your phone, skip down to the Downloading/Installing section of the post.

How to rebuild a Samsung Galaxy S zImage

A friend of mine asked if I could fix his Galaxy S for him. After starting it up and poking around I discovered that the build in flash storage was dead. Since that storage shows up to the system as a SD card, and theres a space for an external SD card, I figured I’d just change some stuff in fstab and be done with it.

It’s a UNIX system, I know this. Right?

Not right.

Unfortunately Android doesn’t store it’s mounts in fstab. No, they’re hardcoded into the init scripts. So change the init scripts and be done with it.


The init scripts are stored in the initrd, which is tacked onto the end of the kernel image in a proprietary Samsungy way. So no standard Android tools will extract it so I can modify it. Of course…

But there is still hope! Fortunately someone has already figured everything out and posted their tools online here.

Using this and the cross compiler found here (I had to modify the kernel repack utils to use this since it’s a different version than they were built for. If you’re getting this far that shouldn’t be a problem for you.) I was able to extract the initrd, modify it to change the device paths, and rebuild the kernel image. Once I had the rebuilt kernel image I flashed it to the phone, as I’ll go into below:

Downloading/installing the kernel

You’ll need a SD card with two MBR FAT32 partitions, the first one should fill most of the card, you can use it for general storage as you would a normal SD card, the second should be about 2-4GB big for the Android /data partition.

I uploaded the custom image I made so that nobody else has to go through this pain.


This kernel is for the XXJW4 firmwares, if you aren’t already running one you need to be on it for it to work. The exact firmware I’m running is available here “(mirror)”:http://terafile.co/268887f61345/XEU-I9000XXJW4-20120405163836.zip but any XXJW4 firmware should work. Google can help you find/install one.

I installed it with Heimdall with the following command:

heimdall flash --KERNEL zImage.new

From within the directory with the zImage.new file you downloaded above. You need to be in download mode (once again, google is your friend) for this obviously.

Once you reboot, your phone should come up like new, but now all storage is on the external SD card. Obviously, this card needs to remain in the phone at all times.