This is by no means new information, and others have posted this many times in other threads. Often, though, folks still ask how to root the Samsung UCLB3 leak or how to root the official AT&T Gingerbread release for the Infuse 4G (both are one and the same at the time of writing this).
Note that this also works for rooting the earlier UCL** and UCK** leaks.
Easiest option - flash a rom that is already rooted.:
The easiest option is to flash this Odin tar.md5 that I put together. It flashes stock UCLB3 with root already installed.:
Another easy option, if you already have cwm recovery, is to download and flash this version.:
And another easy option from qkster to get UCLB3 + cwm recovery in a Heimdall One-Click package.:
More involved option - do it yourself.:
If you're like me, though, and like to do things yourself (or you already have UCLB3 on your phone and need to root it), then below is one way to root the official release and leaked versions.
(Don't have the AT&T GB release or the UCLB3 leak yet? You can get the UCLB3 Gingerbread leak at this link: (http://forum.xda-developers.com/show....php?t=1507658
). Extract the file in 7zip. Place the extracted file in the PDA slot in Odin. Flash.)
To root on your phone.:
(Note: Enable USB debugging in Settings / Applications / Development before performing the heimdall operations below.)
Assuming that you have already flashed the Samsung UCLB3 leak, or that you already have it through AT&T and Kies mini, know these two things.: First, SuperOneClick WILL NOT root this release at the time of writing this. Second, you won't be able to root with the stock kernel, so you will need to flash a custom kernel at least temporarily.
If you intend to go back to the stock UCLB3 kernel after using a custom kernel to root (not a bad idea if you want to keep all stock functionality), then follow this step. If you plan to keep the custom kernel (which allows for improvements such as CWM recovery, Voodoo lagfix, etc.) then skip this step.
If you intend to go back to the stock UCLB3 kernel, save some time and disable Voodoo lagfix by creating a directory on your internal sd card (/sdcard/), labeled Voodoo. Inside that folder, place an empty file named disable-lagfix (with no extension).
If you go back to flash the stock kernel, you will have issues doing so if you have Voodoo lagfix enabled.
Use Heimdall to install a recent custom GB kernel.
Download a recent custom GB kernel. A good custom kernel to use is Entropy's Daily Driver, which can be found at this link.:
Download and install Heimdall on your computer. Follow ALL installation instructions in the README.txt file included with the program, including instructions for installation of the usb driver in zadig. If you don't install the libusb driver that comes with the program, your phone won't be detected, and you'll only receive error messages. Here is the download link.:
Put your Infuse 4G in download mode
Battery pull method: Pull battery, hold down volume keys, replace battery, connect usb cable, and continue to hold volume keys until phone is in download mode.
On your computer, place the custom kernel zImage in the same directory as heimdall.exe. In a command prompt, make this your working directory, and type this into the prompt on your computer.:
heimdall flash --kernel zImage
If kernel flash is successful, the phone will reboot. If you disabled Voodoo lagfix, the phone will boot up without much wait. If you didn't disable Voodoo lagfix, wait for the robotic lady voice to go on about all that is being done to enable Voodoo lagfix. Hope you don't mind waiting. You remember that I suggested that you disable Voodoo lagfix, right?
Download the cwm installable zip at the link below, and place it on your internal sdcard (/sdcard/). You'll flash this in recovery in a moment to get root.
ChainsDD Superuser zip (to flash in cwm recovery):
Put the phone in Recovery Mode.
Button method: With the phone turned off, press and hold both volume buttons, as well as the power button. Release the power button after you see the Samsung logo on screen, and continue to hold the volume buttons.
In recovery, choose "Install zip from sdcard". Select "Choose zip from sdcard", and choose the Superuser zip file that you placed on the internal sd card. Select "Yes -Install zip". When installation is complete, go back in the menu and choose "Reboot system now" After the reboot, you should now have the Superuser program and all system files necessary to be rooted.
If you intend to keep Entropy's custom kernel, then you are done. You have rooted UCLB3 at this point, with a custom kernel.
If you want to flash the stock kernel now, you can do so, and you will keep root. To do that, extract the stock kernel zImage from the leaked Samsung UCLB3 rom linked at the beginning of this tutorial. You can use a program like 7zip to extract the leaked package, and also to extract the tar to get to the zImage. Be sure that Voodoo lagfix is disabled before going back to the stock kernel.
Use the same steps outlined in part e.) of this tutorial to flash the stock zImage (or just use SGS Kernel Flasher).
External sdcard issues?:
If you go back to the stock kernel after flashing a custom kernel, you will most likely have trouble seeing your external sdcard. To fix this, use Root Explorer (or a similar app) to edit /system/etc/vold.fstab. In Root Explorer, browse to /system/etc and choose "Mount R/W" to gain write permission to the directory. Open vold.fstab in the built in text editor. Change the mmc2 in the last line to mmc1. Save and exit. Reboot, and you will regain use of your external sd card.
Hope that helps someone!