Abstract
Samsung Galaxy S II Epic 4G (Touch) (US) <-- the phone with the longest name ever. It's a really nice phone, but lacked a few good software features, one being able to create a mobile hotspot from the phone to share my 4G connection without paying an extra (big) monthly fee. So, I had to root the phone by changing it’s kernel to a rooted kernel. This voids my warranty and is easily detectable by any technician at Sprint if I were to take this phone in for a repair. So, after rooting the system, i simply returned it back to the stock kernel. This keeps the phone rooted, but this leaves the “Superuser” application on the phone. The only way I know of how to remove it is by using the ADB shell. Easy enough.
This by no means is a tutorial, WEAKNET LABS is not responsible for damage you may cause to your phone by following along with me.
I switched to Sprint recently and got this phone:
Root it
You need a new kernel to be root on your new machine. I got mine from “Zedomax.” It’s not great at all, in fact it’s poorly designed, but we only use it temporarily. You can download it from his website here. I grabbed the tarball labeled “SPH-D710_Zedomax_EpicTouchKernel-v3.tar” to use with ODIN.
Next, I downloaded ODIN and Samsung Kies. You will need the drivers for the phone for ODIN to recognize it properly. DO NOT rely on Windows to get the drivers for you. And seriously, don’t follow the weird http://epic4gtouchroot.com/ website, it’s convoluted, is missing information and is just wrong sometimes.
Once you have Kies, simply run the application with the phone plugged in and allow it to say it’s completed and the phone is recognized properly. It will look like iTunes, but for your phone. Heh. You can check the Device Manager to see if the device was recognized or not, but that’s kind of overkill. Simply run ODIN. ODIN will show the device with a yellow label under it like so:
Now, you’re ready to go. If not, try unplugging the device and plugging it back in with Kies open. Next, you NEED to exit Kies completely. make sure the tray icon is gone, and no running process of Kies exists. Kies will screw up the flashing process we do with ODIN and could mess up the firmware in the phone. So, once killed, slam the “PDA” button in ODIN and select the tarball of the new kernel. Here is my file list I am using right now:
the file called acs-eg30-stock-pulled.tar is the stock kernel from the phone someone pulled from the phone before rooting it. We will use that after. Now, hit the “Start” button in ODIN. You will see the progress bar turn green and start to fill up. Once done the default setting of “auto reboot” should simply reboot your phone. At this point, I foo bared the shit out of my phone, over and over trying to get it to work properly with ODIN. I tried making the zip files tarballs, I tried all kinds of weird shit, only to realize that Kies was killing my firmware flashes. :( MAKE SURE IT’S CLOSED!! Now, you should check the kernel in the Settings->About Phone->Kernel. You should see something that says “zedomax.” go into your app drawer and look for this icon:
If found, you’re good to go! Now, try an application, like “Better Terminal Emulator.” Here you can type su and should be prompted to allow the application to use Super User (or root) privileges. Click “remember these settings” and click “Okay.” Now each time you use the application, you can just type “su” and you will see something like so:
Put Stock Kernel Back on There!
As I said before, this kernel made my zedomax just sucks. Radio problems seem to be the worst issue, though there is a quick fix for it, that says to update the Master Subsidy Lock Code. This is used when programming the phone with CDMA. It’s not re-programmed or updated and shouldn’t need to be seeing how this is an intermittent issue. So, it still doesn’t properly resolve the issue. Just put the stock kernel back until someone compiles a better working version. Get the acs-eg30-stock-pulled.tar file from the XDA developers and go through the same process of flashing the phone using ODIN. Make sure that Kies is not open!
Now you’re About phone screen should show this:
And you should still have full root access.
Tethering 4G and creating a WiFi Hotspot (AP)
There are many hotspot applications that can be used with a rooted phone in the android market, but not all can be used with this phone. I used this one: 3.1-beta6 WiFi-Tether
Awesome app, doesn’t work at all with the finicky 3DS, as nothing seems to play right with that damned thing, but it works with XBOX 360, and my laptop just fine.
Remove the SuperUser Application
The only way I know of is to grab the ADB shell here and run it. This requires a bit of command line experience, but it’s simple.
Run the shell:
adb shell
Become root:
su
Mount using Yaffs:
mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system
Remove the files:
rm /system/xbin/su
rm/system/bin/su
rm /system/app/Superuser.apk
reboot:
reboot
Conclusion
So this is how I rooted the phone and got the WiFi Tethering for free. Rooting the device is the easy part, getting other devices to play well with the software AP is the hard part :)
