[AT&T Samsung Galaxy S II SGH-I777] Entropy512:
Multiupload links removed - MU seems to be gone forever. I will repost an unrooted UCKH7 package in the next week along with a modem package - Until then, use the rooted package and then remove:

/system/xbin/su

/system/bin/su

/system/app/Superuser.apk

And then reboot

I have uploaded Heimdall/Odin flashable kernel ,rooted system, and modem images to dev-host. This should be sufficient to unbrick most hosed-up phones, as long as you didn't flash a bad .pit. Note that after flashing this, you might need to wipe data depending on what ROM you were coming from. If you bootloop or things behave wacky, enter 3e recovery (stock kernel means stock recovery) and do a Wipe Data/Factory Reset. If you are reverting from UCKK6 back to UCKH7 you MUST perform this step or wifi will not work. If you're coming from a 100% stock ROM and only using this to gain root, you should be able to keep all your data and not need to wipe.

The kernel is 100% bone stock, the system image is stock except that it is pre-rooted (su binary and Superuser.apk)

I am including the modem in a separate package since that goes in a separate modem slot, and I don't want to reupload a 200+ MB file if I don't have to.

The kernel + rooted UCKH7 system package is here: http://dev-host.org/UWm

Kernel + cache + rooted UCKK6 system package: http://dev-host.org/8LA

Download, extract the package using 7-Zip, which can be downloaded from http://www.7-zip.org/download.html, then either:

1) (Tested on Linux, should work on MacOS) - Extract the tar and flash the components with heimdall from the commandline as follows:

heimdall flash --kernel zImage --factoryfs factoryfs.img

for the kernel + system package, and:

heimdall flash --modem modem.bin

for the modem package

I've never had good results with the Heimdall Frontend GUI.

2) (Tested by Jivy26 for kernel + system, untested for modem) - Flash the .tar in Odin. I'm a Linux user, so I have only tested this with Heimdall so far.

Kernel + system package goes in PDA slot I believe, modem package in Phone slot.

If you are wondering why I used 7-Zip to compress the archive:

7-Zip provides better compression ratios than Zip

7-Zip is open source unlike RAR

If it were a zip file, some doofus would probably think it was CWM-flashable and complain that it didn't flash.

Also - great thanks goes to Jivy26 for providing a stock /system dump. Without that it would not have been possible to make the system image or get a kernel dump.

Coming in the next few days - stock unrooted /system package.

Also just added - a param.lfs backup from my device. This is NOT contained in an Odin-flashable .tar file yet, I'll work on cleaning up my packages when I'm feeling better. I came down with a nasty cold a few days ago.

UPDATE:

creepyncrawly has written an EXCELLENT step-by-step guide for flashing this with Odin. The guide is at:

http://xdaforums.com/showthread.php?t=1313659

In addition, he posted an Odin-flashable tar package for just the stock kernel, for those who want to do a ! removal. I have mirrored the file (I don't trust Dropbox for long-term hosting) at http://www.multiupload.com/MD7SMMNG24 - his original post is at http://xdaforums.com/showpost.php?p=18535109&postcount=174